I want to differentiate A from B and want to use the 'cast a ... glance at' structure. What adjective should I use:
"cast a differentiating/discriminating/? glance at A and B"
Neither is a common collocation: BNC notes neither one. But 'a discriminating glance' doesn't mean what you want it to - it is the sort of glance characteristic of a discriminating person' - someone who has what is sometimes called 'good taste' (and what at one time was just called 'taste').