Familiar master, inwardly curious, heading for dormitory (10)
I believe the answer is:
acquainted
'familiar' is the definition.
(similar in meaning)
'master inwardly curious heading for dormitory' is the wordplay.
I cannot really understand how this works, but
'curious' could be 'quaint' (I've seen this before) and 'quaint' is found within the answer.
'master' could be 'ace' (ace can mean an expert) and 'ace' is found in the leftover letters.
A single letter 'd' remains which might be clued in a way I don't see.
This explanation may well be incorrect...
(Other definitions for acquainted that I've seen before include "Notified" , "on good terms" , "Well-versed" , "Made aware of" , "knowing a little" .)