| Verb | 1. | topple - fall down, as if collapsing; "The tower of the World Trade Center tumbled after the plane hit it"come down, descend, go down, fall - move downward and lower, but not necessarily all the way; "The temperature is going down"; "The barometer is falling"; "The curtain fell on the diva"; "Her hand went up and then fell again" keel over - turn over and fall; "the man had a heart attck and keeled over" | |