trip,
slip an unintentional but embarrassing blunder; "he recited the whole poem without a single trip"; "he arranged his robes to avoid a trip-up later"; "confusion caused his unfortunate misstep"
descend,
come down,
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 attack and keeled over"
tumble -
fall suddenly and sharply; "Prices tumbled after the devaluation of the currency"
drop give birth; used for animals; "The cow dropped her calf this morning"
tumble -
suffer a sudden downfall, overthrow, or defeat
worsen,
decline grow worse; "Conditions in the slum worsened"
tumble -
put clothes in a tumbling barrel, where they are whirled about in hot air, usually with the purpose of drying; "Wash in warm water and tumble dry"