A proverb meaning that gossip and rumors don't last long—after some time (traditionally 75 days) people move on; don't worry too much about them.
彼女のスキャンダルは騒がれたが、結局は人の噂も七十五日ですぐに収まった。
Her scandal caused a stir, but in the end the gossip died down after a while.
今は色々言われているが、人の噂も七十五日だ。気にしない方がいい。
People are saying many things now, but gossip won't last forever. It's better not to worry about it.
ネットの炎上も長続きしないことが多い。人の噂も七十五日ということだ。
Online flammability often doesn't last long. It's true that gossip doesn't stick around forever.