mostly as in in large part

• "mainly or chiefly"
• "These accounts are largely inactive"

Synonyms

• largelyin large part; on a large scale
• for the most partin large part

mostly as in usually

• "as a rule"
• "by and large it doesn't rain much here"

Synonyms

• by and largeusually
• generallyusually; without distinction of one from others; without regard to specific details or exceptions
• more often than notusually