Generally in the majority (6)
I believe the answer is:
mostly
'generally' is the definition.
(synonyms)
'majority' is the wordplay.
I cannot really see how this works, but
'majority' could be 'most' (most of a group) and 'most' is located in the answer.
This explanation may well be incorrect...
'in the' acts as a link.
Can you help me to learn more?
(Other definitions for mostly that I've seen before include "On the whole" , "In large part" , "For the greater part; usually" , "More often than not" , "Largely" .)