Like a hole in the head? (3)
I believe the answer is:
ear
'hole in the head?' is the definition.
(I've seen this in another clue)
'like a' is the wordplay.
I cannot really understand how this works, but
'a' is found in the answer.
The remaining letters 'er' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for ear that I've seen before include "Seed-bearing part of corn" , "'Give every man thine ..., but few thy voice' (Hamlet)" , "It's used in hearing" , "Appreciation of sounds" , "Aural appendage" .)