Poor trip abroad, on balance (10)
I believe the answer is:
proportion
'balance' is the definition.
(I've seen this before)
'poor trip abroad on' is the wordplay.
'abroad' is an anagram indicator.
'poor'+'trip'='poortrip'
'poortrip' with letters rearranged gives 'proporti'.
'proporti'+'on'='PROPORTION'
(Other definitions for proportion that I've seen before include "Part - one needs a sense of it" , "balance" .)