Chant, ingesting acid and turning on (8)
I believe the answer is:
starting
'turning on' is the definition.
'chant ingesting acid' is the wordplay.
'chant' becomes 'sing' (I've seen this before).
'ingesting' means one lot of letters goes inside another.
'acid' becomes 'tart'.
'sing' going around 'tart' is 'STARTING'.
'and' acts as a link.
(Other definitions for starting that I've seen before include "Disturbing" , "Rousing" , "Beginning; jumping" , "showing sudden alarm" , "Commencing" .)