1.  landslide(n = noun.event) - an overwhelming electoral victory; "Roosevelt defeated Hoover in a landslide"
is a kind of triumph, victory

2.  landslide(n = noun.event) landslip - a slide of a large mass of dirt and rock down a mountain or cliff;
is a kind of slide
has particulars: mudslide, rockslide

1.  The slipping down of a mass of land from a mountain, hill, etc. [1913 Webster]

2.  The land which slips down. [1913 Webster]

3.  An election victory in which the winning candidate receives a substantial majority of the votes, usually meaning at least ten per cent more than any opposing candidate. [PJC]

4.  Any overwhelming victory. [PJC]

landslide, n.
1 the sliding down of a mass of land from a mountain, cliff, etc.
2 an overwhelming majority for one side in an election.

N  descent, descension, declension, declination, fall, falling, slump, drop, plunge, plummet, cadence, subsidence, collapse, lapse, downfall, tumble, slip, tilt, trip, lurch, cropper, culbute, titubation, stumble, fate of Icarus, avalanche, debacle, landslip, landslide, declivity, dip, hill, rappel, descending, descendent, decurrent, decursive, labent, deciduous, nodding to its fall, downhill, downwards, the bottom fell out.