Initially Omani spy aims to disturb meetings (8)
I believe the answer is:
symposia
'meetings' is the definition.
(symposium is a kind of meeting)
'initially omani spy aims to disturb' is the wordplay.
'initially' suggests taking the first letters.
'to disturb' is an anagram indicator (I've seen 'disturbed' mean this (the order of letters is disturbed)).
The initial letter of 'omani' is 'o'.
'o'+'spy'+'aims'='ospyaims'
'ospyaims' with letters rearranged gives 'SYMPOSIA'.
(Other definitions for symposia that I've seen before include "Academic conferences" , "Specialist conferences" .)