on thin ice, to be/skate

skate on thin ice

Fig. to be in a risky situation. (Fig. on the image of someone taking the risk of ice skating on thin ice.) I try to stay well informed so I don't end up skating on thin ice when the teacher asks me a question. You are skating on thin ice when you ask me that!
See also: ice, on, skate, thin
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs.

on thin ice, to be/skate

A hazardous course of action or conversation. “In skating over thin ice our safety is in our speed,” wrote Ralph Waldo Emerson in his essay Prudence (1841). Literally, it is possible to skate over very thin ice without breaking through if one glides quickly enough, but Emerson was already using the expression figuratively.
See also: on, skate, thin
The Dictionary of Clichés by Christine Ammer
See also:
  • be skating on thin ice
  • be skating/walking on thin ice
  • skate on thin ice
  • skating on thin ice
  • freeze over
  • kiss and cry
  • kiss and cry area
  • kiss and cry corner
  • slid
  • slide along