The phenomenon of words sounding like their meaning is called phonaesthesia.
Phonaesthesia isn't quite onomatopoeia, which is a direct imitation of a sound. Instead, it's a subtle but pervasive association between certain sounds and meanings. Think of words containing 'gl-,' which often relate to light, like 'glimmer,' 'gleam,' or 'glow'—suggesting our brains are wired to make sound-meaning connections!