accost comes from Middle French accoster ('to approach, draw alongside'), from Vulgar Latin accostāre ('to come alongside'), from Latin ad- ('to') + costa ('rib, side'). Morphologically, the word is transparent as a compound: its parts remain visible in the modern spelling, while the older history of those parts supplies the deeper ancestry. In modern use, the verb sense is "to approach and speak to someone boldly or aggressively", which keeps the etymology connected to the word's present dictionary value rather than treating it as a merely historical label. The wider word family includes related English forms such as coast, coastal, showing how the same base continues to support neighboring English vocabulary. The principal historical forms in the chain include Vulgar Latin accostāre, Latin costa, which anchor the explanation in named linguistic material.