Tight-lipped Tom is back before I go round (8)
I believe the answer is:
taciturn
'tight-lipped' is the definition.
(taciturn means not saying much)
'tom is back before i go round' is the wordplay.
'tom' becomes 'cat' (a tom is a male cat).
'is back' says the letters should be written backwards.
'before' means one lot of letters go next to another.
'go round' becomes 'turn' (both can mean to rotate).
'cat' back-to-front is 'tac'.
'tac'+'i'+'turn'='TACITURN'
(Other definitions for taciturn that I've seen before include "Not inclined to conversation" , "Uncommunicative, of few words" , "Disinclined to speak" , "Tending to silence" , "Untalkative" .)