Build Steel is a term that pertains to the act of constructing or assembling something using steel as its primary material. However, this phrase can also be dissected into two distinct words: build and steel, which have their own set of antonyms. Build, as a verb, can be the opposite of deconstruct, demolish, or dismantle. It can also be the antonym of break, ruin, or destroy. On the other hand, Steel, as a noun, can have antonyms such as wood, plastic, or paper. As a verb, Steel can mean to strengthen, but it can also have antonyms such as weaken, damage, or harm.