Worker housed in modest shack (6)
I believe the answer is:
shanty
'shack' is the definition.
('shanty' can be a synonym of 'shack')
'worker housed in modest' is the wordplay.
'worker' becomes 'ant' (worker is a type of ant).
'housed in' indicates putting letters inside.
'modest' becomes 'shy'.
'ant' going into 'shy' is 'SHANTY'.
(Other definitions for shanty that I've seen before include "Sailor's song or derelict building" , "Crude dwelling - sailor's song" , "Sailor's work song - ramshackle hut" , "Roughly built hut" , "Sea song - hovel" .)