Cornered by sea inlet? (2,3)
I believe the answer is:
at bay
'cornered' is the definition.
('at bay' can be a synonym of 'cornered')
'by sea inlet?' is the wordplay.
'by' becomes 'at'.
'sea inlet?' becomes 'bay' (I've seen this before).
'at'+'bay'='AT BAY'
(Other definitions for at bay that I've seen before include "Forced to turn and face the attackers" , "Cornered, trapped" .)