The guy's Italian worker must be uncertain (8)
I believe the answer is:
hesitant
'uncertain' is the definition.
(I've seen this before)
'the guy's italian worker' is the wordplay.
'the guy's' becomes 'he's'.
'italian' becomes 'it' (abbreviation for Italian).
'worker' becomes 'ant' (worker is a type of ant).
'hes'+'it'+'ant'='HESITANT'
'must be' acts as a link.
(Other definitions for hesitant that I've seen before include "Uncertain, nervous" , "Demurring" , "Undecided, halting" , "Reluctant (to speak, act)" , "Slow through indecision" .)