Be unable to find toilets, we hear (4)
I believe the answer is:
lose
'be unable to find' is the definition.
(I've seen this in another clue)
'toilets we hear' is the wordplay.
'toilets' becomes 'loos' (loo can informally mean a toilet).
'we hear' indicates a 'sounds like' (homophone) clue.
'loos' sounds like 'LOSE'.
(Other definitions for lose that I've seen before include "Fail to win" , "Mislay - fail" , "Mislay or be defeated" , "go down" , "Shake off (a pursuer)" .)