High Quality Content by WIKIPEDIA articles! A relative clause is a subordinate clause that modifies a noun phrase, most commonly a noun. For example, the phrase "the man who wasn`t there" contains the noun man, which is modified by the relative clause who wasn`t there. A relative clause can also modify a pronoun, as in "he to whom I have written", or a noun phrase which already contains a modifier, as in "the black panther in the tree, which is about to pounce". The complete phrase (modified noun phrase plus modifying relative clause) is also a noun phrase.