Basic concept of drunkard about to secure work (5)
I believe the answer is:
topos
'basic concept' is the definition.
'drunkard about to secure work' is the wordplay.
'drunkard' becomes 'sot' ('sot' can be a synonym of 'drunkard').
'about' says the letters should be written in reverse.
'to secure' means one lot of letters goes inside another.
'work' becomes 'op' (abbreviation for opus).
'sot' in reverse letter order is 'tos'.
'tos' placed around 'op' is 'TOPOS'.
'of' acts as a link.
(Other definitions for topos that I've seen before include "Literary stock theme" , "Stock item" .)