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
.