Meaning : In large part. Mainly or chiefly.
Example :
These accounts are largely inactive.
Synonyms : for the most part, largely
Meaning : Usually. As a rule.
Example :
By and large it doesn't rain much here.
Synonyms : by and large, generally, more often than not
Mostly ka meaning, vilom shabd, paryayvachi aur samanarthi shabd in Hindi. Mostly ka matlab kya hota hai?