The term PART OF KISS can be broken down into three crossword solutions: KEEP (4 letters), STUPID (6 letters), and KEEPIT (6 letters). KEEP is a verb meaning to retain possession of something, while STUPID is an adjective meaning lacking intelligence or common sense. KEEPIT is a portmanteau of the two words KEEP and IT, suggesting that one should KEEP something. Together, these three solutions suggest that one should retain possession of something, even if it may seem STUPID.