Fitting in leads to really uneasy recruit experiencing joy (7)
I believe the answer is:
rapture
'joy' is the definition.
(I know that rapture is a type of joy)
'fitting in leads to really uneasy recruit experiencing' is the wordplay.
'fitting' becomes 'apt' (both mean appropriate).
'in' indicates putting letters inside.
'leads to' suggests taking the first letters.
The initial letters of 'really uneasy recruit experiencing' is 'rure'.
'apt' inserted within 'rure' is 'RAPTURE'.
(Other definitions for rapture that I've seen before include "Exaltation" , "Bliss, intense delight" , "Feeling of bliss, elation" , "Transports of delight" , "modified for Nanki-Poo?" .)