Every so often, accused gives signal (3)
I believe the answer is:
cue
'signal' is the definition.
(thesaurus)
'every so often accused' is the wordplay.
'every so often' indicates alternate letters.
The alternating letters of 'accused' are 'CUE'.
'gives' acts as a link.
(Other definitions for cue that I've seen before include "Rod used in billiards" , "Actor's words" , "On a car[D?] this would give a prompt" , "Sign" , "Sporting rod" .)