As was shown in the comment, both 変　（へん）　and 可笑しい　（おかしい - the kanji literally mean "can laugh," so you can imagine why it gets that meaning.） are acceptable terms for the concept of "weird." In conversation, you'll hear: それは変ですね。/それはおかしいですね Here are some other words to express similar ideas: 奇怪　（きかい） - weird, strange 奇妙　（きみょう） - curious, strange (I feel like this is used mostly to describe things that can't be perceived clearly; ex: 奇妙な音を聞こえました。 = I heard a strange noise) 不思議　（ふしぎ） - mysterious, strange

おかしい=Okashii 変=hen I've seen both of those used I've also been told that if you say that towards a person it can be very disrespectful. They usually try to not use those words directed at people.