Lost where a sailor is found (2,3)
I believe the answer is:
at sea
'lost' is the definition.
(I've seen this before)
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for at sea that I've seen before include "All bothered and bewildered" , "Confused (in the main?)" , "On a ship (out of one's depth?)" , "stumped" , "Away from land" .)