know your onions

know (one's) onions

To be very knowledgeable or skilled in some area. Primarily heard in UK, Australia. I think Nicole is our best candidate for the job—when it comes to corporate accounting, she really knows her onions.
See also: know, onion
Farlex Dictionary of Idioms.

know your onions

BRITISH, OLD-FASHIONED
If you know your onions, you know a lot about a particular subject. She really knows her onions in the historical field. Note: This may derive from the rhyming slang `onion rings', meaning `things'.
See also: know, onion
Collins COBUILD Idioms Dictionary, 3rd ed.

know your onions

be fully knowledgeable about something. informal
Onions is perhaps short for rhyming slang onion rings , meaning ‘things’. The phrase dates from the 1920s.
See also: know, onion
Farlex Partner Idioms Dictionary
See also:
  • know (one's) onions
  • know (one's) stuff
  • know one's stuff
  • know stuff
  • know your stuff
  • have a good command of
  • have a good command of (something)
  • know about
  • know about (someone or something)
  • triple threat
References in periodicals archive
O be flexible enough to fit into an oversized pickle jar, you've got to know your onions. It's a case of squeezy does it.
BIRTHDAY GIRL BETH'S GOT BOTTLE; Mum organises daring circus stunt for 21st birthday treat
Know your onions Plant out shallots and onion sets into the garden.
Jobs for the week
| Know your onions: Let the top flop over by themselves | Know your onions: Let the top flop over by themselves
ASK CAROL
And you've really got to know your onions to be successful betting on it.
Smelling the scent of victory, but the truth is I don't know my onions and I've run out of Lynx
EXPERTS are warning that you need to know your onions before foraging for mushrooms.
Get the facts before you go picking mushrooms
KNOW YOUR ONIONS: Ruth Jones, from Wirral Watercress, tries out some alternative earrings TASTY: Alexa, from French Corner, uses her loaf at Wirral Food Festival while, below left, Shirley Roberts, from Shirley''s Pie, tries one of her homemade offerings Pictures: JAMES MALONEY DANCING QUEENS: Katy Preston and Felicity Newton dance about in the mud SHOW TIME: Neil Smith, from Uselesskillz, entertains
Basking in success
Captions like "know your onions", "UPA lands in onion soup", "Onions: Weep till March", "More at work than onions" regularly chide the national government over the matter.
Food and Economy - The Onion War
KNOW YOUR ONIONS: Graham Onions believes in England
Onions has big warning for the England critics
This is the perfect time of the year to get to know your onions - or more exactly their flowers.
flowers: Get to know your onions; Let stunning alliums bring elegance to your home this autumn
GARSTON-based Can Cook wants to get Liverpool cooking, so if you don't know your onions and fancy learning how to cook in your spare time, why not join their latest campaign?
Free courses are cooking on gas; Advertising Feature
So if you know your onions you'll pop along to your local Focus DIY store right now.
FREE SPRING BULBS
KNOW YOUR ONIONS: Vegetable judge, Bob Herbert makes a decision over the onions and left, gladioli judge Derek Roscow makes a decision (AC140810Cshow-10)
Flower show bursts into bloom again
IF you're going on TV's Who Wants To Be A Millionaire, you have really got to know your onions.
pounds 7,000 pasta blaster; Who Wants to be Millionaire gloom for Ed but super joy for Mark
2 Know your onions - tradition tells us that Boxing Day is the best time to sow your onions.
Best of the Bunch Wintergreen and other Gaultherias; 5 MIN INTERVIEW Notebook
Make sure you know your onions! Delve into a veritable A-Z of greens (and reds, yellows, oranges) with Vegetables by Sylvia Gabet (Hachette Illustrated, pounds 14.99).
Remember to meet your greens