Follow or adapt (6)
I believe the answer is:
tailor
'adapt' is the definition.
(tailoring is a kind of adapting)
'follow or' is the wordplay.
'follow' becomes 'tail' (I've seen this before).
'tail'+'or'='TAILOR'
(Other definitions for tailor that I've seen before include "person before soldier and sailor in list" , "Outfitter" , "Suit maker" , "Person who cuts clothes" , "Specially adapt" .)