Is cost a verb?
“Cost” can be either a noun or a verb.
As a noun, “cost” can refer to the money needed to buy or do something (e.g., “the cost of housing is too high”) or the loss something requires or results in (e.g., “the war was won, but at the cost of many lives”).
As a verb, “cost” is usually a transitive and stative verb used to describe the price of something or the loss resulting from something (e.g., “her new suit cost $500,” “her credit card debt cost her her marriage”).
In professional environments, “cost” can be used as an action verb meaning to calculate how much something will be (e.g., “we need to cost the new project”). The simple past tense of “cost” in this context is “costed.”