腐敗 （フハイ） decomposition, putrefaction, putrescence, spoilage, corruption, degeneracy, decay, depravity

腐心 （フシン） taking great pains (to do), making every effort, having a lot of trouble (doing), racking one's brains

防腐 （ボウフ） preservation from decay, prevention of putrefaction, embalmment, antisepsis

高野豆腐 （コウヤドウフ） freeze-dried tofu

腐る （くさる） to rot, to go bad, to decay, to spoil, to fester, to decompose, to turn sour (e.g. milk), to corrode, to weather, to crumble, to become useless, to blunt, to weaken (from lack of practice), to become depraved, to be degenerate, to be morally bankrupt, to be corrupt, to be depressed, to be dispirited, to feel discouraged, to feel down, to have the audacity to, to be bastard enough to, to lose a bet, to be drenched, to become sopping wet

腐るほど （くさるほど） more than one can possibly use, countless (e.g. examples), (money) to burn, rolling in (cash)

腐れる （くされる） to spoil, to rot, to corrode

腐れ （くされ） rotting, spoiling, decaying, corroding, rotten, worthless, paltry, contemptible

腐れ縁 （くされえん） (undesirable but) inseparable relationship

腐らす （くさらす） to let spoil, to leave to rot, to cause to rot, to corrode, to discourage, to dishearten

腐す （くさす） to speak ill of