Eggs initially thrown in mass meeting? It's true! (6)
I believe the answer is:
really
'true' is the definition.
Both the answer and definition are adverbs. Perhaps you can see an association between them that I can't see?
'eggs initially thrown in mass meeting?' is the wordplay.
'initially' says to take the initial letters.
'thrown in' is an insertion indicator.
'mass meeting?' becomes 'rally' (synonyms).
The initial letter of 'eggs' is 'e'.
'e' going into 'rally' is 'REALLY'.
'it's' acts as a link.
Can you help me to learn more?
(Other definitions for really that I've seen before include "In genuine way" , "as a matter of fact" , "In truth - one may be surprised to say it" , "without a doubt" , "are you sure?" .)