Socially inept person acquires right language (5)
I believe the answer is:
greek
'language' is the definition.
(Greek is an example)
'socially inept person acquires right' is the wordplay.
'socially inept person' becomes 'geek' (I've seen this before).
'acquires' is an insertion indicator.
'right' becomes 'r' (common abbreviation).
'geek' going around 'r' is 'GREEK'.
(Other definitions for greek that I've seen before include "Hellenic" , "Classical language" , "Nationality" , "Athenian?" , "Supposedly unknown language?" .)