The term '90s Nifty' refers to the period of time in the 1990s when the economy was booming and technology was advancing rapidly. The term is often used to describe the era of economic growth and technological advancement that occurred during this decade. The crossword solution for the term '90s Nifty' is PHAT, which stands for Pretty Hot And Tempting. This phrase was popularized by the hip-hop group OutKast in their song 'So Fresh, So Clean' and has since become a slang term for something that is attractive or desirable.