Synonyms for Lessen:

n.

chip away, shrivel, mute, dilute, weaken. increase, let up, rebate, peter, tail away. comfort. lessen (noun)
decrease, minify, fall, diminish, subside.

v.

alleviate (verb)
alleviate, allay, moderate, relieve, assuage, mitigate, soothe, palliate, ease.
decrease (verb)
decrement, abridge, contract, lower, shorten, deflate, deplete, concentrate, abate, curtail, subside, dwindle, abbreviate, drain, decrease, shrink, die down, diminish, truncate, compress, erode, deduct, compact, recede.
detract (verb)
defame, derogate, detract, discount, disparage, cast aspersion, malign, abrade, depreciate, decry.
diminish (verb)
lighten, downgrade, prune, weed, condense, trim, cull, bob, reduce, shear, nip, taper, crop, clip, pare, shave, minimize.
lessen (verb)
subordinate.
lessening (verb)
subordinate, diminish.
lighten (verb)
unload.
lower, reduce (verb)
dilute, clip, cut, mitigate, shrink, drain, dwindle, curtail, abate, decrease, truncate, minify, abridge, lighten, die down, taper, ease, erode, weaken, crop, minimize, diminish, contract, moderate.
subtract (verb)
cut, elide, dock, delete, subtract.

Other synonyms:

chip away, weaken, peter. comfort, rebate, dilute. mute. curtail
minify.
decrease
die down, taper, peter.
lighten
lighten.
lower
lower.
peter
tail away.
recede
recede.
shorten
elide.
Other relevant words:
fall, mute, peter, rebate, shrivel, tail away, weaken, comfort, minify, dilute.

Usage examples for lessen

  1. He was careful to attribute his success, not to any skill or courage of his own, but to fortune, being willing to lessen his glory to avoid the ill- will of mankind. – Plutarch's Lives Volume III. by Plutarch
  2. But that doesn't lessen my obligations, and I'm going to take every possible care of you and your child, Sabina, whether you come or not. – The Spinners by Eden Phillpotts
  3. Yet she had studied with all her most anxious care to write him an answer; such a one as might not lessen her understanding, which he had often praised, in his esteem. – Nature and Art by Mrs. Inchbald