1. superlative form of phat; most excellent, impressive, or cool
Usage: slang; informal; chiefly used in hip-hop and youth culture

Examples

• That's the phattest beat I've heard all year.
• She showed up in the phattest outfit at the party.
• The phattest part of the concert was the final encore.
• His new sneakers are straight-up phattest.
• That track has the phattest production quality.