Uncalled-for heckles ending in distress (8)
I believe the answer is:
needless
'uncalled-for' is the definition.
(synonyms)
'heckles ending in distress' is the wordplay.
'heckles' becomes 'needles' (I've seen this before).
'ending in' indicates one should take the final letters.
The final letter of 'distress' is 's'.
'needles'+'s'='NEEDLESS'
(Other definitions for needless that I've seen before include "without provocation?" , "Superfluous" , "Unneccessary and unwarranted" , "Excessive" , "Unnecessary, avoidable" .)