Phony means fake or insincere. A phony person pretends to be something they're not, like someone who acts friendly to your face but talks badly about you behind your back. A phony story is made up or exaggerated to impress others. When something is phony, it's not genuine or real.

You might call a smile phony if you can tell the person doesn't really mean it. Their mouth might be smiling, but their eyes aren't. A phony excuse is one that sounds reasonable but isn't true, like saying “my dog ate my homework” when you just forgot to do it. The word carries a sense of disappointment: we expect authenticity and get pretense instead.

The opposite of phony is genuine or authentic. When your friend congratulates you on winning the spelling bee and you can tell they really mean it, that's genuine. When they force a smile and quickly change the subject, you might sense something phony.

People can spot phonies more easily than phonies realize. If you try to act like an expert on something you don't understand, or pretend to like things just because they're popular, others eventually notice the disconnect between what you're saying and who you really are.