the word "whoo" is a prime example of onomatopoeia, a linguistic formation where the sound of the word directly imitates the sound it represents. it belongs to a large class of expressive interjections in english, like "wow" or "phew," that are created to mimic human exclamations or environmental noises. its origin is not traced to a classical root but emerges naturally from the phonetic repertoire of the language to convey immediate emotional or auditory experiences. as such, its "logic" is purely sound-symbolic, evolving directly from a vocal imitation into a standardized lexical item for expressing excitement, surprise, or calling for attention.

this is a simplex word. it is an onomatopoeic formation, imitating a sound such as a cry of excitement, a shout, or the blowing of wind.