a mexican who tries to act black

A portmanteau of carpe diem, a Latin phrase that means “Seize the Day!” and DM, which stands for Direct Messages. This word means seizing the day via DMs.

A migger is a mexican who acts like a black person.

A "Migger" is someone who is from Michigan and is a Gamer. The longer form is MI-Gamer, or, Michigan Gamer. MIG is short for MichiganGamer, however, add 'ger (to emphasize Michigander) to the end and you have Migger. In Michigan, a Migger is known as a local gamer who originated or lives in Michigan.