expression, godan verb (-su)
flip-flop; do an about-face; change attitude suddenly
Idiomatic expression describing a sudden, complete reversal of opinion, attitude, or behavior, often with a negative connotation of inconsistency or opportunism. Literally 'to flip over one's palm'.
彼は昨日まで賛成だったのに、今日は手のひらを返したように反対した。
He was in favor until yesterday, but today he opposed it as if he had completely changed his mind.
上司は都合が悪くなるとすぐに手のひらを返す。
My boss flip-flops as soon as things become inconvenient for him.
expression, godan verb (-su)
do something easy; do with ease
Rare idiomatic use meaning to accomplish something effortlessly, as easily as turning over one's hand. Not commonly used in modern Japanese; the primary sense is the about-face meaning.
彼は難しい問題を手のひらを返すように解いた。
He solved the difficult problem as easily as turning over his hand.