They join men maybe involved in a row (4)
I believe the answer is:
oars
'row' is the definition.
Although both the answer and definition are nouns, they are not in the same form of the noun. However, I know that 'row' relates to this answer.
'they join men maybe involved in a' is the wordplay.
I cannot really see how this works, but
'a' is within the answer.
'men' could be 'or' (military abbreviation for other ranks) and 'or' is present in the remaining letters.
A single letter 's' remains 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 oars that I've seen before include "Means of propulsion" , "Paddles" , "Henley sportsmen" , "Implements of propulsion on water" , "Soar with propellors" .)