Nuttish

Part of speech: adjective

Definitions

1. Characterized by playful absurdity and quirky habits that hint at eccentric traits
2. Exhibiting odd and whimsical behavior that deviates from the mainstream in an amusing way
3. Showing a lively and unconventional manner that is slightly odd but entertaining

Etymology: "Nuttish" is a plain formation: the noun "nut," used in its slang sense of an eccentric or crazy person, with the suffix "-ish," which attaches to nouns to mean "having the qualities of" or "somewhat like." So a nuttish person is one who behaves a bit like a nut, which is to say somewhat odd, unpredictable or eccentric in manner. The noun "nut" in this sense is itself a figurative extension. It draws on the older idea of the head as a nut, a hard shell around the brain, and "nut" has long been used for a head and then for a person whose head is judged to be unsound. The slang sense of an eccentric is the one that carries into "nuttish," so the adjective inherits its flavour from that informal usage rather than from anything botanical. Because the word is built from two ordinary English parts, it needs no borrowing from another language, and its meaning follows directly from the parts: a little nutty, but in a quirky rather than alarming way.