intransitive verb sank or sunk, sunk, sinking sink′·ing

1. to go beneath the surface of water, deep snow, soft ground, etc. so as to be partly or completely covered
2. to go down slowly; fall or descend gradually
3. to appear to fall or descend the sun sinking in the west
4. 1. to become lower in level; diminish in height or depth a lake that has sunk three inches
   2. to slope downward (from, to, etc.)
5. to diminish or decrease in degree, volume, or strength; subside, as wind, flames, a sound, spirits, etc.
6. to become lower in value or amount; lessen, as prices, funds, etc.
7. to seem or become hollow or shrunken; recede, as the cheeks or eyes
8. to pass gradually (into sleep, despair, lethargy, etc.)
9. to become increasingly and dangerously ill; approach death; fail
10. 1. to lose position, wealth, prestige, dignity, etc.
    2. to lose or abandon one's moral values and stoop (to some unworthy action)
11. to become absorbed; penetrate

Etymology: ME sinken < OE sincan, akin to Ger sinken < IE base *sengw-, to fall, sink > Gr heaphthē, (he) sank

transitive verb

1. to cause to submerge or go beneath the surface to sink a boat, to sink a spade into the ground
2. to cause or allow to fall or go down; lower
3. to make (a well, mine, engraved design, etc.) by digging, drilling, or cutting
4. to cause to penetrate or become absorbed
5. to reduce in volume, amount, degree, or intensity
6. 1. to invest (money, capital, etc.)
   2. to lose by investing
7. to hold back, suppress, or conceal (evidence, identity, personal interests, etc.)
8. to pay up (a debt)
9. 1. to cause to lose courage, strength, etc. or position, dignity, etc.
   2. to debase (character, dignity, etc.)
10. to defeat; undo; ruin
11. ☆ Sports to put (a basketball, golf ball, etc.) through the net, into the cup, etc. so as to score

noun

1. a cesspool or sewer
2. any place or thing considered morally filthy or corrupted
3. any of various basins, as in a kitchen or laundry, connected with a drainpipe and, usually, a water supply
4. a repository or device for collecting, removing, or absorbing energy, heat, a specific substance, etc. from a system and then disposing of or dissipating it
5. ☆ Geol.
   1. an area of slightly sunken land, esp. one in which water collects, often forming a salt lake, or disappears by evaporation or percolation into the ground
   2. sinkhole (sense )

Etymology: ME sinke < the v.