ADJ
- open, undone
- His tie was knotted below his open collar. His collar was undone
- button-down, turned-down
- tight
- starched, stiff
- detachable
- coat, shirt, etc.
- high, stand-up, wing
- clerical, dog
- The vicar had his dog collar on
VERB + COLLAR
- have
- The shirt had a button-down collar
- have on, wear
- button, do up, fasten
- unbutton, undo, unfasten
- raise, turn up
- She turned up her coat collar for extra warmth
- turn down
- loosen
PHRASES
- collar and tie
- He wore a collar and tie for the occasion
VERB + COLLAR
- have on, wear
- slip
- The dog slipped its collar and ran off