Mammoth Uncensored Word List:
33 words ending with op, 9 letters long

bellyflop blooddrop carrottop codevelop cottontop coughdrop eavesdrop hammerkop hectoflop intercrop interloop nicompoop nonlaptop outgallop paintshop paratroop printshop redevelop sharecrop shortstop stageprop stonecrop sweatshop sweetshop tallyshop technopop truckstop turboprop underprop waterdrop woodentop yottaflop zettaflop