Articulate English Liberal backed moderate (3,2)
I believe the answer is:
let up
'moderate' is the definition.
(thesaurus)
'articulate english liberal backed' is the wordplay.
'articulate' becomes 'put' (putting is a kind of articulating).
'english' becomes 'E' (abbreviation as in OED).
'liberal' becomes 'l' (abbreviation).
'backed' shows that the letters should be reversed in order.
'put'+'e'+'l'='putel'
'putel' in reverse letter order is 'LET-UP'.
(Other definitions for let up that I've seen before include "Relent, relax" , "break" , "stop" , "allowed out of bed?" , "Pause, respite" .)