Unable to relax (3,2,4)
I believe the answer is:
ill at ease
'unable to relax' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for ill at ease that I've seen before include "Elite, alas? (Anag)" , "Nervous, uncomfortable" , "appear uncomfortable" , "awkward" , "Fidgety" .)