becoming liquid (verb) thaw: unfreeze, warm
Sinonime: brainteaser, bugaboo, cliff-hanger,
conundrum,
enigma,
example, grabber,
illustration,
intricacy, mind-boggler,
mystery, poser, puzzler,
query,
riddle, sixty-four thousand dollar question, stickler, stumper, teaser, twister
Antonime: solution