Synonyms for Blues:

adj.

musical (adjective)
instrumental, jazz, bebop, vocal, melodic, lyric, concert, tune, musical, symphonic, syncopated, harmonious.

n.

gloom, sorrow, distress, remorse, regret, disappointment, grief. dirge, ambient, bluegrass, backing, backup, bhangra, acid jazz, background music, lament, funk, acid house. mope, happy, dysphoria, feelings, dumps, doldrums, despondence, heavy-heartedness, unhappiness, dolefulness. blues (noun)
megrims.
boredom (noun)
ennui.
dejection (noun)
despair, depression, dejection, wistfulness, woefulness, mournfulness, moroseness, downheartedness, anguish, misery, discouragement, anxiety, melancholy, pensiveness, sullenness, despondency, moodiness, grimness, glumness, gloominess, disheartenment, dolorousness, plaintiveness, dreariness, sadness, joylessness, ennui, contemplativeness, dispiritedness.
depression (noun)
moodiness, mournfulness, glumness, gloominess, despondency, sadness, melancholy, unhappiness, doldrums, dumps, gloom, dejection.
dismay (noun)
disheartenment.
dumps (noun)
gloominess, dreariness, cheerlessness, woefulness.
music (noun)
score, carol, air, lullaby, syncopation, psalm, song, arrangement, lyric, chorus, aria, concerto, sonata, instrumental, ditty, ballet, serenade, ballad, quartet, bebop, concert, composition, hymn, symphony, music, jazz, melody, tune, vocalization, harmony.
weariness (noun)
weakness, faintness, cheerlessness, apathy, exhaustion, tiredness, flaccidity, boredom, tedium, debilitation, droopiness, drowsiness, fatigue, weariness, over-weariness, listlessness, feebleness, footsoreness, sleepiness.

Other synonyms:

dolefulness, ambient, doldrums, backing, bluegrass, bhangra, acid jazz, background music, heavy-heartedness, dysphoria, acid house. dumps, unhappiness, despondence. backup, gloom. funk. Other relevant words:
mope, gloom, dysphoria, disappointment, doldrums, regret, funk, heavy-heartedness, grief, sorrow, dolefulness, ambient, dirge, bluegrass, megrims, happy, backing, lament, unhappiness, backup, dumps, distress, bhangra, remorse, despondence, feelings.

Usage examples for blues

  1. Sometimes- when I am in the blues I feel as if that night was the only time in my life when I was really and truly of use. – Betty Trevor by Mrs. G. de Horne Vaizey
  2. I've a good mind to be off again to- night; this sort of thing would give the happiest man the blues – The Red Rat's Daughter by Guy Boothby