这个其实可以有很多的翻译方法,应该结合具体的语境啊~
如果只是单纯的表述说谎不好的话可以很简单地说:Maybe it's really a bad idea to lie.
如果是针对某个人或者某件事:It's not good for him/her lying about something(撒谎的事).或者 It's not good for him/her lying to somebody(撒谎的对象).
严肃一点的话可以说:It is not appropriate for lying.
介于你加了‘也许’,我猜你想要大概语气不那么生硬吧,那就用第一个好了~