Without qualification accepts lieutenant in refuge (7)
I believe the answer is:
shelter
'refuge' is the definition.
(I've seen this before)
'without qualification accepts lieutenant' is the wordplay.
'without qualification' becomes 'sheer' (sheer can mean total or unmitigated).
'accepts' is an insertion indicator.
'lieutenant' becomes 'lt' (abbreviation for lieutenant).
'sheer' placed around 'lt' is 'SHELTER'.
'in' is the link.
(Other definitions for shelter that I've seen before include "Sanctuary, protection" , "Refuge, protection" , "retreat" , "'Refuge, cover (7)'" , "Protection; charity for the homeless" .)