decay

1 to go through decomposition the logs decayed on the rain forest floor the atom of plutonium decayed in the test chamber Synonyms break down, corrupt, decompose, disintegrate, fester, foul, mold, molder, perish [chiefly British], putrefy, rot, spoil Related Words sour, turn, turn off [British]; contaminate, defile, pollute, taint; addle, curdle, ferment; mortify; rust; crumble, decline, degenerate, descend, deteriorate, dilapidate, sink, wither Phrases fall apart, go to seed (or run to seed) Near Antonyms age, develop, grow, mature, ripen; refresh, renew, restore; cleanse, purify; assemble, compose, integrate; ameliorate, better, improve, meliorate

2 to become worse or of less value the restaurant's standards for food and service had decayed over the years Synonyms atrophy, crumble, deteriorate, decline, degenerate, descend, devolve, ebb, regress, retrograde, rot, sink, worsenRelated Words abate, de-escalate, diminish, downsize, dwindle, recede, wane; break down, corrupt, decompose, degrade, dilapidate, disintegrate, molder, putrefy; sour, spoil; lessen, lower, reduce; debilitate, undermine; droop, fail, fall, flag, lag, languish, run down, sag, slip, waste (away), weaken, wiltNear Antonyms better, upgrade; enhance, enrich, fortify, heighten, intensify, strengthen; advance, develop, march, proceed, progressAntonyms ameliorate, improve, meliorate

3 to lose bodily strength or vigor having reached her 80s, the woman could sense that her body was decaying Synonyms weaken, droop, emaciate, fade, fail, flag, go, lag, languish, sag, sink, waste (away), wilt, witherRelated Words break down, wear out; yield; degenerate, deteriorate, rot, run downNear Antonyms convalesce, rally, rebound, recover, recuperate; gain