Go after poor act I, saying little (8)
I believe the answer is:
taciturn
'saying little' is the definition.
(I've seen this before)
'go after poor act i' is the wordplay.
'go' becomes 'turn' ('turn' can be a synonym of 'go'**).
'after' says to put letters next to each other.
'poor' is an anagram indicator.
'act' with letters rearranged gives 'tac'.
'tac'+'i'='taci'
'turn' put after 'taci' is 'TACITURN'.
(Other definitions for taciturn that I've seen before include "Untalkative" , "Without saying much" , "Talking little" , "Aloof" , "Not inclined to conversation" .)