WordNet sense 1 (cause to topple or tumble by pushing):

tip, topple

WordNet sense 2 (fly around):

whirl, whirl around

WordNet sense 3 (fall apart):

collapse, crumble, crumple, break down

WordNet sense 4 (understand, usually after some initial difficulty):

twig, catch on, get it, latch on, cotton on, get onto, get wise

WordNet sense 5 (a sudden drop from an upright position):

fall, spill