A small measure of familiarity (3)
I believe the answer is:
mil
'a small measure' is the definition.
'mil' can be an answer for 'measure' (mil is a kind of measure). I am unsure of the 'a small' bit.
'of familiarity' is the wordplay.
'of' says the answer is hidden in the clue.
'MIL' can be found hidden inside 'familiarity'.
Can you help me to learn more?
(Other definitions for mil that I've seen before include "One / one thousand inch" , "One thousanth of an inch" , "tiny distance" , "One thousandth of an inch" .)