Other hyponyms of lessen include
break,
shrink,
shrivel,
taper,
drop off,
fly,
vanish,
vaporize,
break,
ease off,
ease up,
flag,
slacken off,
weaken,
boil down,
concentrate,
decoct,
reduce,
contract,
shrink,
shrink,
shrivel,
shrivel up,
wither,
abate,
let up,
slack,
slack off,
deflate,
dwindle,
dwindle away,
dwindle down,
remit,
de-escalate,
depreciate,
devaluate,
devalue,
undervalue,
shorten,
thin out,
decline,
go down,
wane,
wane,
wane,
decelerate,
retard,
slow,
slow down,
slow up,
decrescendo.