It guides the ploughman (6)
I believe the answer is:
tiller
'the ploughman' is the definition.
(I've seen this before)
'it guides' is the wordplay.
I cannot quite see how this works, but
'it' could be 't' (abbreviation. e.g. in 'tis) and 't' is found within the answer.
The remaining letters 'iller' 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 tiller that I've seen before include "Bar that turns rudder in small boat" , "Steering lever" , "Shoot" , "Boat's steering bar" , "Handle for turning rudder" .)