Sample trial with hesitation (6)
I believe the answer is:
tester
'sample' is the definition.
(I've seen this before)
'trial with hesitation' is the wordplay.
'trial' becomes 'test' (synonyms).
'with' is a charade indicator (letters next to each other).
'hesitation' becomes 'er' (sound made while hesitating - um, er).
'test'+'er'='TESTER'
(Other definitions for tester that I've seen before include "old coin" , "Someone examining" , "One who tries out - canopy" , "One pumps" , "Kind of examiner or bed canopy" .)