Sample pitted fruit — it's dull (6)
I believe the answer is:
sedate
'dull' is the definition.
(I've seen this before)
'sample pitted fruit' is the wordplay.
'pitted' suggests removing the centre (to pit something is to remove its insides).
'fruit' becomes 'date' (date is a kind of fruit).
'sample' with its centre removed is 'se'.
'se'+'date'='SEDATE'
'it's' is the link.
(Other definitions for sedate that I've seen before include "Calm, not lively" , "Calm, sober" , "Decorous" , "Dignified - staid" , "Quiet and rather dull" .)