Synonyms for Irritable:

adj.

all (adjective)
cranky, fractious, nettlesome, peckish, peevish, pettish, petulant, techy, testy, tetchy.
angry (adjective)
bitter, ill-tempered, splenetic, sulky, sullen, passionate.
bad-tempered (adjective)
ill-natured.
brittle (adjective)
edgy, nervous, short.
cantankerous (adjective)
bad-tempered, captious, cranky, critical, crusty, disagreeable, ill-natured, quarrelsome, snappish, sour.
captious (adjective)
acrimonious, crabby.
crabby/crabbed (adjective)
acid, churlish, glum, tart.
cranky (adjective)
grumpy, hot-tempered, mean, tetchy, ugly, out of sorts.
cross (adjective)
pettish, waspish.
crotchety (adjective)
curmudgeonly.
excitable (adjective)
ardent, brittle, combustible, edgy, emotional, excitable, explosive, fiery, fragile, high-strung, hot-tempered, impulsive, nervous, passionate, quick-tempered, rash, reckless, sensitive, short-tempered, stormy, tempestuous, volatile, volcanic, cranky, crusty, touchy.
fractious (adjective)
fractious.
ill-tempered (adjective)
crabbed.
impressionable (adjective)
sensitive.
irritable (adjective)
acerbic, acid, acrimonious, annoyed, bearish, bellicose, bitter, brooding, cantankerous, carping, caustic, choleric, churlish, complaining, contentious, crabbed, cranky, cross, crotchety, crusty, disputatious, dissatisfied, fiery, fractious, fretful, gloomy, grouchy, grumbling, huffy, hypercritical, ill-humored, irascible, moody, morose, peevish, petty, petulant, plaintive, prickly, querulous, quick-tempered, resentful, sensitive, snappish, snappy, sour, spiteful, surly, tart, tense, testy, touchy, Fretting, Snarling, out of humor, easily offended.
sensitive (adjective)
thin-skinned, annoyed, brooding, captious, carping, choleric, complaining, contentious, critical, crotchety, curmudgeonly, disputatious, dissatisfied, fidgety, fretful, gloomy, glum, grouchy, gruff, grumbling, grumpy, hypercritical, hypersensitive, ill-humored, ill-tempered, moody, morose, plaintive, quarrelsome, querulous, resentful, short, shrewish, snappy, splenetic, sulky, sullen, tense, waspish, Fretting, Snarling, out of humor, having a short fuse, easily offended, pickle-pussed, sour-bellied.
sullen (adjective)
grumpy, sulky.
temperamental (adjective)
temperamental.

n.

temperamental. attitude, bad-tempered, crabby, disagreeable, fretful, grouchy, grumpy, ill-tempered, mean, nasty, querulous, snappy, ugly, waspish, out of sorts. irritable (noun)
cranky, excitable, fractious, ill-natured, nettlesome, peckish, peevish, pettish, petulant, sensitive, techy, testy, tetchy.

Other synonyms:

bad-tempered, complaining, curmudgeonly, disagreeable, hypercritical, shrewish. snappy. ugly. nasty. bad-tempered
quarrelsome, waspish.
brusque
gruff.
cross
ill-tempered, sulky.
curt
short.
discontented
grumbling.
eccentric
crotchety.
fretful
querulous.
ill-humored
morose.
moody
temperamental.
peevish
crabby, fretful, splenetic.
surly
grouchy.
touchy
ill-humored.
unsociable
sullen.
Other relevant words:
annoyed, bad-tempered, brooding, captious, carping, choleric, complaining, contentious, crabby, critical, crotchety, curmudgeonly, disagreeable, disputatious, dissatisfied, fidgety, fractious, fretful, gloomy, glum, grouchy, gruff, grumbling, grumpy, hypercritical, hypersensitive, ill-humored, ill-natured, ill-tempered, mean, moody, morose, nasty, nettlesome, peckish, pettish, plaintive, quarrelsome, querulous, resentful, short, shrewish, snappy, splenetic, sulky, sullen, techy, temperamental, tense, testy, tetchy, thin-skinned, ugly, waspish, Fretting, Snarling, out of humor, easily offended.

Usage examples for irritable

  1. My aunt Dorothy's eyes dwelt kindly on him to encourage him, but the man's irritable nose was again his enemy. – The Adventures of Harry Richmond, Complete by George Meredith Last Updated: March 7, 2009
  2. Not even tobacco would soothe Romayne's wasted and irritable nerves. – The Black Robe by Wilkie Collins
  3. I do it all myself: when any one helps me I am jealous and irritable till I am rude. – The Lady with the Dog and Other Stories by Anton Chekhov