Idioms are phrases which cannot be understood simply by looking at the meaning of the individual words in the phrase.
Idiom:
take off after (someone or something)
Meaning:
to begin to chase someone or something
Example:
The fox took off after the rabbit which jumped out of the hole.
List of common idioms, their meanings and examples of their usage in sentences
An expression in the usage of a language that is peculiar to itself either in having a meaning that cannot be derived from the conjoined meanings of its elements or in its grammatically atypical use of words.