Can a perposition be used as a verb?
A preposition is used with a verb to be called a prepositional verb. Instances of the same would help you understand the concept better:
I seek for your blessings.
He was asked to look after my grandmother.
An idiomatic expression that combines a verb and a preposition to make a new verb with a distinct meaning.
The preposition in a prepositional verb must be followed by a noun or pronoun, and so all prepositional verbs are transitive. Also, the object must come after the preposition.