A phrasal verb is a verb that is combined with a preposition (at, on, over, etc.) or adverb (back, down, off, etc.), and together has its own special meaning. For example, get away means escape; and speak up means speak louder.

Some phrasal verbs retain the meaning of the original verb while some others have meaning completely different to the original verb.
EXAMPLE: I asked them to come in. (The phrasal verb come in means enter which is easily understood as we are familiar with the meaning of the words: come, in.)
EXAMPLE: The deal fell through at the last minute. (The phrasal verb fell through means not completed successfully which is different in meaning to the verb fell.)

Phrasal verbs can be separable or non-separable. When a phrasal verb is separable, a noun object comes after the participle of the phrasal verb or comes between the verb and the participle. (A participle is the word that is used in a phrasal verb. Examples of participle: at, in, on, off, away, etc.) If a phrasal verb is non-separable, a noun or pronoun always comes after the participle.