unremitting (adj.)

• abiding
• ageless
• ardent
• articulated
• assiduous
• ceaseless
• changeless
• connected
• constant
• continual
• continued
• continuing
• continuous
• cyclical
• dateless
• diligent
• direct
• dogged
• endless
• enduring
• energetic
• eternal
• everlasting
• faithful
• featureless
• fervent
• hard
• hardworking
• immediate
• immemorial
• immutable
• inalterable
• incessant
• incommutable
• inconvertible
• indefatigable
• indefeasible
• indestructible
• indomitable
• industrious
• inert
• infinite
• insistent
• interminable
• invariable
• invincible
• irretrievable
• irreversible
• irrevocable
• joined
• laborious
• lasting
• linked
• loyal
• monotonous
• never-ending
• noble
• nonreturnable
• nonreversible
• nonstop
• obstinate
• oscillating
• patient
• perdurable
• perennial
• periodic
• permanent
• perpetual
• persevering
• persistent
• persisting
• pertinacious
• plodding
• preoccupied
• rapid
• rapt
• recurrent
• regular
• relentless
• remaining
• repeated
• repetitive
• resolute
• round-the-clock
• running
• seamless
• sedulous
• sempiternal
• serried
• single-minded
• sleepless
• smooth
• stable
• staccato
• steadfast
• steady
• sticking
• straight
• strenuous
• stubborn
• sustained
• tenacious
• timeless
• tireless
• unalterable
• unaltered
• unbroken
• unceasing
• unchangeable
• unchanged
• unchanging
• unconquerable
• undaunted
• undeviating
• undifferentiated
• undiscouraged
• undying
• unending
• unfailing
• unfaltering
• unflagging
• unflinching
• uniform
• uninterrupted
• unmodifiable
• unrelenting
• unrelieved
• unsleeping
• unsparing
• unsusceptible
• unswerving
• untiring
• unvarying
• unwavering
• unwearied
• unwearying
• vehement
• zealous