Gag pitiful person uttered (5)
I believe the answer is:
retch
'gag' is the definition.
(I've seen this before)
'pitiful person uttered' is the wordplay.
'pitiful person' becomes 'wretch' (I've seen this before).
'uttered' indicates a 'sounds like' (homophone) clue.
'wretch' sounds like 'RETCH'.
(Other definitions for retch that I've seen before include "Sound and seem to vomit" , "Try to be sick" , "Strain to be sick" , "Strain as if to vomit" , "Heave (as if to vomit)" .)