The man who goes straight will follow it (4)
I believe the answer is:
nose
'the man' is the definition.
(thesaurus)
'goes straight will follow it' is the wordplay.
I cannot quite understand how this works, but
'it' could be 'e' ('e' can mean 'electronic' which is similar to 'IT') and 'e' is located in the answer.
The remaining letters 'nos' is a valid word which might be clued in a way I don't understand.
This explanation may well be incorrect...
'who' is the link.
Can you help me to learn more?
(Other definitions for nose that I've seen before include "Pry" , "In-your-face" , "Olafactory organ" , "Olfactory organ" , "Bouquet of wine; beak" .)