One goth, terribly busy (2,3,2)
I believe the answer is:
on the go
'busy' is the definition.
(similar in meaning)
'one goth terribly' is the wordplay.
'terribly' indicates anagramming the letters.
'one'+'goth'='onegoth'
'onegoth' with letters rearranged gives 'ON THE GO'.
(Other definitions for on the go that I've seen before include "Active, always doing something" , "Active, in constant motion" , "Active and energetic" , "Very active (colloq.)" , "Very busy, in constant motion" .)