One's sat by guitar when back with Motörhead (4)
I believe the answer is:
exam
'one's sat' is the definition.
Although both the answer and definition are singular nouns, I don't understand how one could define the other.
'guitar when back with motorhead' is the wordplay.
'guitar when' becomes 'axe' (I can't justify this - if you can you should believe this answer much more).
'back' shows that the letters should be reversed in order.
'with' means one lot of letters go next to another.
'motorhead' becomes 'm' (head letter of 'motor').
'axe' reversed gives 'exa'.
'exa'+'m'='EXAM'
'by' acts as a link.
Can you help me to learn more?
(Other definitions for exam that I've seen before include "Test (abbrev.)" , "paper" , "One might be taken for English" , "Student test" , "Educational test" .)