Synonyms for On purpose:

adv

•deliberately (adverb)
by design.

adv.

•deliberately (adverb)
advisedly.
•on purpose (adverb)
intentionally, deliberately, purposely, by design.
•purposely (adverb)
designedly.

n.

•on purpose (noun)
intentionally, deliberately, advisedly, designedly, purposely, by choice, by design.

Other synonyms:

•Other relevant words:
deliberately.