Adapt to having internal trouble, right? (6)
I believe the answer is:
tailor
'adapt' is the definition.
(I know that tailor is a more specific form of the action adapt)
'to having internal trouble right?' is the wordplay.
'having internal' is an insertion indicator.
'trouble' becomes 'ail' (synonyms).
'right?' becomes 'r' (common abbreviation).
'to' going around 'ail' is 'tailo'.
'tailo'+'r'='TAILOR'
(Other definitions for tailor that I've seen before include "Specially adapt" , "Rialto (anag) -- adjust to a specific need" , "Maker of fitted clothes" , "Maker of men's suits" , "person before soldier and sailor in list" .)