A riff is (1) a short, rhythmic phrase played on an instrument, especially in jazz, blues, or rock music, or (2) a clever or inventive spoken commentary. The word also works as a verb, usually followed by the preposition on, meaning to make a clever or inventive spoken commentary. A rift is (1) a narrow fissure, or (2) a break in friendly relations. As a verb (very rarely used), rift means to split open.
Examples
You may have heard a bracing guitar riff from Gang of Four’s Andy Gill on TV recently. [Boston Herald]
U.S. Pressure on Mubarak Opens a Rift With Arab Allies [Wall Street Journal]
Later issued on an album, his freewheeling riff on race, religion, drugs and society at large became the quintessential example of his work. [New York Post]
A rift developed in Kenya’s coalition government on Saturday as Prime Minister Raila Odinga declared “null and void” key judiciary appointments made by the president. [Independent Online]
The opening riff to his tune “Lose Yourself” eerily starts in and Eminem cruises the city. [BusinessWeek]