Obtain article in spirit (4)
I believe the answer is:
gain
'obtain' is the definition.
(gaining is a kind of obtaining)
'article in spirit' is the wordplay.
'article' becomes 'a' (example of the part-of-speech).
'in' means one lot of letters goes inside another.
'spirit' becomes 'gin' (I've seen this before).
'a' put into 'gin' is 'GAIN'.
(Other definitions for gain that I've seen before include "Earn, profit" , "Pick up" , "Advance" , "Win" , "Benefit; increase in value" .)