grandmother

(Do) you kiss your grandmother with that mouth?

Used to express shock and disapproval toward someone who is using lewd, vulgar, or obscene language. Stop cursing around all these little kids! Geez, you kiss your grandmother with that mouth? Wow, those are some mighty vulgar words for a 10-year-old to know. Do you kiss your grandmother with that mouth, young man?
See also: grandmother, kiss, that

(one) could be (someone's) (parent/grandparent)

One is old enough to be someone else's parent or grandparent. Used in reference to two people who are or may become romantic or sexual partners, especially to indicate that the speaker thinks such a pairing would be inappropriate. He's going out with Mary from the legal department? But she could be his mother! I don't feel comfortable with this. I could be your grandfather, for heaven's sake!
See also: could

(one) is old enough to be (someone's) (parent/grandparent)

One is old enough to be someone else's parent or grandparent. Used in reference to two people who are or may become romantic or sexual partners, especially to indicate that the speaker thinks such a pairing would be inappropriate. He's going out with Mary from the legal department? But she's old enough to be his mother! I don't feel comfortable with this. I'm old enough to be your grandfather, for heaven's sake!
See also: enough, old

don't teach your grandmother to suck eggs

An older person is wiser and more experienced and worldly than a young person may think—thus, the older person does not need to be taught. I may be 70, but I've been using a computer since before you were born! Don't teach your grandmother to suck eggs, sonny!
See also: egg, grandmother, suck, teach

teach (one's) grandmother (how) to suck eggs

To try to teach an older person who is wiser, more experienced, and more worldly than a young person may think. Why are you explaining basic typing to Ethel? Sure, she's 70, but she's been using a computer since before you were born—quit teaching your grandmother to suck eggs! These young hotshots come in and try to prove they know the ropes better than we do, like they're teaching their grandmothers how to suck eggs.
See also: egg, grandmother, suck, teach
Farlex Dictionary of Idioms.

teach one's grandmother to suck eggs

Fig. to try to tell or show someone more knowledgeable or experienced than oneself how to do something. Don't suggest showing Mary how to knit. It will be like teaching your grandmother to suck eggs. Don't teach your grandmother to suck eggs. Bob has been playing tennis for years.
See also: egg, grandmother, suck, teach
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs.

teach your grandmother to suck eggs

BRITISH
If you teach your grandmother to suck eggs, you give advice about a subject to someone who knows more about it than you do. Look, I don't want to teach my grandmother to suck eggs, but haven't you done this the wrong way round? Note: You can also say that you teach your granny to suck eggs. At the risk of teaching my granny to suck eggs, wouldn't it be better to use this pan?
See also: egg, grandmother, suck, teach
Collins COBUILD Idioms Dictionary, 3rd ed.

teach your grandmother to suck eggs

presume to advise a more experienced person.
The proverb you can't teach your grandmother to suck eggs has been used since the early 18th century as a caution against any attempt by the ignorant or inexperienced to instruct someone wiser or more knowledgeable.
See also: egg, grandmother, suck, teach
Farlex Partner Idioms Dictionary

teach your grandmother to suck ˈeggs

(British English, informal) tell or show somebody how to do something that they can already do well, and probably better than you can: I don’t know why he’s telling Rob how to use the computer. It seems to me like teaching your grandmother to suck eggs.
See also: egg, grandmother, suck, teach
Farlex Partner Idioms Dictionary
See also:
  • (Do) you kiss your grandmother with that mouth?
  • (Do) you kiss your granny with that mouth?
  • (Do) you kiss your mama with that mouth?
  • (Do) you kiss your momma with that mouth?
  • Do you kiss your momma with that mouth?
  • Do you eat with that mouth?
  • (Do) you eat with that mouth?
  • (Do) you kiss your mother with that mouth?
  • cheesehead
  • anyone would think...
References in classic literature
Little Red-Cap, however, had been running about picking flowers, and when she had gathered so many that she could carry no more, she remembered her grandmother, and set out on the way to her.
how uneasy I feel today, and at other times I like being with grandmother so much.' She called out: 'Good morning,' but received no answer; so she went to the bed and drew back the curtains.
'But, grandmother, what big eyes you have!' she said.
Fairy Tales
While grandmother took the pitchfork we found standing in one of the rows and dug potatoes, while I picked them up out of the soft brown earth and put them into the bag, I kept looking up at the hawks that were doing what I might so easily do.
When grandmother was ready to go, I said I would like to stay up there in the garden awhile.
Grandmother swung the bag of potatoes over her shoulder and went down the path, leaning forward a little.
My Antonia
Astley gravely, but also with alacrity, "that I am indeed glad to see you in such good health." This was interpreted to the Grandmother, and she seemed much gratified.
Again the Grandmother was borne aloft and carried down the staircase amid a perfect bevy of followers--the General walking as though he had been hit over the head with a cudgel, and De Griers seeming to be plunged in thought.
Gambler
The grandmother was ill at the time and he himself was out of work.
Later he was caught and his grandmother settled the mat- ter by offering to come twice a week for a month and scrub the shop.
After Tom lost his place at Banker White's he did not live with his grandmother, although often in the evening she came to visit him.
Winesberg Ohio
"The same as usual, my dear, my glass is there on the table -- give it to me, Valentine." Valentine poured the orangeade into a glass and gave it to her grandmother with a certain degree of dread, for it was the same glass she fancied that had been touched by the spectre.
de Villefort left the room, and Valentine seated herself at the bedside of her grandmother. The poor child appeared herself to require the doctor she had recommended to her aged relative.
Count of Monte Cristo
That was another thing, Grandmother Majauszkiene interrupted herself-- this house was unlucky.
They had begun to question the old lady as to why one family had been unable to pay, trying to show her by figures that it ought to have been possible; and Grandmother Majauszkiene had disputed their figures-- "You say twelve dollars a month; but that does not include the interest."
Jungle