Rot (verb)
To suffer decomposition due to biological action, especially by fungi or bacteria.
Rot (verb)
To decline in function or utility.
Rot (verb)
To (cause to) deteriorate in any way, as in morals; to corrupt.
Rot (verb)
To make putrid; to cause to be wholly or partially decomposed by natural processes.
"to rot vegetable fiber"
Rot (verb)
To spend a long period of time (in an unpleasant place).
"to rot in prison"
"to rot in Hell"
Rot (verb)
To expose, as flax, to a process of maceration, etc., for the purpose of separating the fiber; to ret.
Rot (noun)
The process of becoming rotten; putrefaction.
Rot (noun)
Any of several diseases in which breakdown of tissue occurs.
Rot (noun)
Verbal nonsense.

Wiktionary

Rot (verb)
(chiefly of animal or vegetable matter) decay or cause to decay by the action of bacteria and fungi; decompose
"the chalets were neglected and their woodwork was rotting away"
"caries sets in at a weak point and spreads to rot the whole tooth"
Rot (verb)
gradually deteriorate, especially through neglect
"the education system has been allowed to rot"
Rot (verb)
make fun of; tease
"has anybody been rotting you?"
Rot (noun)
the process of decaying
"the leaves were turning black with rot"
Rot (noun)
rotten or decayed matter.
Rot (noun)
any of a number of fungal or bacterial diseases that cause tissue deterioration, especially in plants.
Rot (noun)
liver rot in sheep.
Rot (noun)
a process of deterioration; a decline in standards
"there is enough talent in the team to stop the rot"
"it was when they moved back to the family home that the rot set in"
Rot (noun)
corruption on the part of officials.
Rot (noun)
nonsense; rubbish
"don't talk rot"
"‘Rot!’ she said with vehemence"

Oxford Dictionary

Rot (verb)
To undergo a process common to organic substances by which they lose the cohesion of their parts and pass through certain chemical changes, giving off usually in some stages of the process more or less offensive odors; to become decomposed by a natural process; to putrefy; to decay.
Rot (verb)
Figuratively: To perish slowly; to decay; to die; to become corrupt.
Rot
To make putrid; to cause to be wholly or partially decomposed by natural processes; as, to rot vegetable fiber.
Rot
To expose, as flax, to a process of maceration, etc., for the purpose of separating the fiber; to ret.
Rot (noun)
Process of rotting; decay; putrefaction.
Rot (noun)
A disease or decay in fruits, leaves, or wood, supposed to be caused by minute fungi. See Bitter rot, Black rot, etc., below.
Rot (noun)
A fatal distemper which attacks sheep and sometimes other animals. It is due to the presence of a parasitic worm in the liver or gall bladder. See 1st Fluke, 2.

Webster Dictionary

Rot (noun)
decay usually accompanied by an offensive odor
Rot (noun)
(biology) decaying caused by bacterial or fungal action
Rot (noun)
unacceptable behavior (especially ludicrously false statements)
Rot (verb)
break down;
"The bodies decomposed in the heat"
Rot (verb)
waste away;
"Political prisoners are wasting away in many prisons all over the world"