sombrero

the word 'sombrero' entered english directly from spanish, where it means 'hat' or, more specifically, 'shade-maker'. the spanish term derives from 'sombra', meaning 'shade', which itself originates from the latin 'umbra' (shadow, shade), with the addition of the prefix 'sub-' (under) influencing the initial 's' sound. the literal sense of 'shade-maker' perfectly describes the hat's primary function of providing shade from the sun. over time, in english, the term became specialized to refer almost exclusively to the distinctive wide-brimmed hat associated with mexico and spanish culture.

this is a loanword from spanish. it is not productively segmented into smaller, meaningful english morphemes.