(v): undergo a change in bodily posture
(v): cause to sink
(v): cause to move or shift into a new position or place, both in a concrete and in an abstract sense
(v): pass into a specified state or condition
(v): go or proceed from one point to another
(v): go under, "The raft sank and its occupants drowned"
(v): move downward and lower, but not necessarily all the way
(v): descend into or as if into some soft substance or place
(v): move downward and lower, but not necessarily all the way
(v): appear to move downward
(v): go down
(v): fall heavily or suddenly; decline markedly
(v): go down in value
(v): fall or sink heavily
(v): break down, literally or metaphorically
(v): embed deeply
(v): fix or set securely or deeply
(n): plumbing fixture consisting of a water basin fixed to a wall or floor and having a drainpipe
(n): a fixture for the distribution and use of water in a building
(n): (technology) a process that acts to absorb or remove energy or a substance from a system
(n): a process existing in or produced by nature (rather than by the intent of human beings)
(n): a depression in the ground communicating with a subterranean passage (especially in limestone) and formed by solution or by collapse of a cavern roof
(n): a sunken or depressed geological formation
(n): a covered cistern; waste water and sewage flow into it
(n): an artificial reservoir for storing liquids; especially an underground tank for storing rainwater
This doesn't work for me as a substitute for 'six'; it's too close to the French 'cinq' (five).