He drops a line hoping for some response (6)
I believe the answer is:
angler
'he drops a line hoping for some response' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
'he drops a line' is the wordplay.
I cannot quite understand how this works, but
'a' could be 'an' and 'an' is located in the answer.
'line' could be 'l' (used when specifying particular lines from a poem) and 'l' is located in the answer.
The remaining letters 'ger' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for angler that I've seen before include "Strait; -- of Lochalsh" , "One proverbially exaggerating" , "I cast Rod" , "Isaac Walton wrote of the 'Compleat' one" , "Fisher with hook and line." .)