# [tinylisp], 18 bytes

There's a library function for that.

    (load library)odd?

The function itself is `odd?`--call it like `(odd? 12)`. [Try it online!]

Writing a function from scratch is **28 bytes** ([TIO]):

    (d o(q((n)(i(l n 2)n(o(s n 2

This defines `o` as: if `n` is less than 2, return `n`, else recurse with `n-2`.

[tinylisp]: https://github.com/dloscutoff/Esolangs/tree/master/tinylisp
[Try it online!]: https://tio.run/nexus/tinylisp#@6@Rk5@YopCTmVSUWFSpyaWRm1igkJ@SYq@gkZNZXKJgqGCkYKxgomBkqWBkbKxgZGFsYKGp@f8/AA "tinylisp – TIO Nexus"

[TIO]: https://tio.run/nexus/tinylisp#@6@RopCvUaihkaepkamRo5CnYKSZp5GvUQxi/dcEAy6NfAUjYxPN/wA