avoidable comes from avoid + -able. Avoid derives from Anglo-French avoider, from Old French esvuidier ('to empty out'), from es- (Latin ex-, 'out') + vuidier ('to empty'), from Latin vocivus/vacivus ('empty'). Morphologically, the word is transparent: -able is attached to the older base named in the history, so the modern form packages an inherited or borrowed stem inside a later English derivative. In modern use, the adjective sense is "able to be prevented or kept away from", 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 avoid, avoidance and derivatives such as avoidably, avoidability, showing how the same base continues to support neighboring English vocabulary. The principal historical forms in the chain include Latin vacivus, which anchor the explanation in named linguistic material.