Adapt (6)
'adapt' is the definition.
(I know that adapt can be written as adjust)
This is the entire clue.
(Other definitions for adjust that I've seen before include "Modify - tweak" , "Make small changes" , "Alter by small amount to make right for use" , "Alter slightly to be right for use" , "Adapt (oneself)" .)
(Other definitions for tailor that I've seen before include "Rialto (anag) -- adjust to a specific need" , "Maker of garments" , "Person who cuts clothes" , "Specially adapt" , "One makes fitted clothes" .)
(Other definitions for modify that I've seen before include "Alter slightly" , "Make partial changes to" , "Reshape" , "Partially change" , "Change slightly to fit" .)