The word 'trombonist' is a modern English formation that combines the name of the instrument with an agent suffix. The instrument's name, 'trombone', entered English from Italian in the 18th century, itself derived from 'tromba' meaning 'trumpet' and the augmentative suffix '-one', literally meaning 'large trumpet'. The suffix '-ist', with roots in Greek '-istes', was adopted into Latin and subsequently into European languages to denote a practitioner of an art or skill. Thus, a trombonist is logically 'one who plays the large trumpet', directly linking the physical instrument to the person who performs on it.

Structure: trombone + ist - trombone: Italian origin, from 'tromba' (trumpet) + the augmentative suffix '-one' (large). Refers to the musical instrument. - ist: A suffix of Greek origin via Latin, forming agent nouns denoting a person who practices or is concerned with something.