Worker on short holiday showing no interest (6)
I believe the answer is:
vacant
'showing no interest' is the definition.
(as in a vacant stare)
'worker on short holiday' is the wordplay.
'worker' becomes 'ant' (worker is a type of ant).
'on' says to put letters next to each other.
'short holiday' becomes 'vac' (short for vacation).
'ant' put after 'vac' is 'VACANT'.
(Other definitions for vacant that I've seen before include "Empty, unoccupied" , "unemployed" , "Not occupied, perhaps apartment" , "Not filled, job or house" , "blankly incurious" .)