Cough, and pass me up a letter (3)
I believe the answer is:
hem
'cough' is the definition.
Although both the answer and definition are singular nouns, I can't understand how one could define the other.
'pass me up a letter' is the wordplay.
I cannot quite see how this works, but
'letter' could be 'he' (he is a kind of letter) and 'he' is found in the answer.
A single letter 'm' remains which might be clued in a way I don't understand.
This may be the basis of the clue (or it may be nonsense).
'and' acts as a link.
Can you help me to learn more?
(Other definitions for hem that I've seen before include "may attract attention" , "Express hesitation" , "Border; fringe" , "Bottom of a garment" , "Stitched edge of garment" .)