Yes, rot is a synonym for nonsense.
Yes, rot is a proper word.The word rot is a verb (rot, rots, rotting, rotted):Paper money will rot if you bury it in the ground without moisture protection.The word rot is a noun (uncountable, mass noun):The potatoes show some rot so we should throw them out.Some compound nouns for the noun rot: root rot, dry rot, brown rot, black rot, boll rot, etc.The noun 'rot' is sometimes used as slang for 'nonsense'.
Decompose
nonsense
rot
nonsense
rot
produce and decay
Usually food that can rot easily is referred to as highly perishable.
The noun 'rot' is a common, concrete, uncountable noun; a word for the process of rotting or the condition of being rotten; a disease of plants or animals marked by the decay of tissue; an area of decayed tissue. The noun 'rot' is a common, abstract noun as an informal term for pointless talk, nonsense.
News Newt noise not no nonsense
Poppycock is nonsense.
Decay is a word for dead things/rot.