bastardize comes from bastard plus the verb suffix -ize; bastard is from Old French bastard, probably from bast ('packsaddle') plus -ard. Morphologically, the word is transparent: -ize and -ard 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 verb sense is "to corrupt or debase by adding impure or inferior elements", 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 bastard, bastardy, bastardly and derivatives such as bastardization, showing how the same base continues to support neighboring English vocabulary. The principal historical forms in the chain include Old French bastard, which anchor the explanation in named linguistic material.