Phrasal verbs, also called two-word verbs, are idiomatic expressions wherein the second element of the verb (the adverb or particle) is not necessarily predictable.
Phrasal Verb:
lead someone on
Meaning / Example:
1. to guide someone onward. > We led him on so he could see more of the gardens.
2. and lead someone on to tease someone; to encourage someone's romantic or sexual interest without sincerity. > You are just leading me on! > It's not fair to continue leading him on.
A phrase that combines a verb with a preposition or adverb or both and that functions as a verb whose meaning is different from the combined meanings of the individual words.