The Oxford Thesaurus An A-Z Dictionary of Synonyms INTRO ...

unrelieved, stiff, hard, stiff-necked, rigid, obstinate,
adamant, obdurate, intransigent, determined, unswerving,
undeviating, intractable, persevering, steely, tough,
intransigent, unsparing, uncompromising, pitiless, unforgiving,
ruthless, merciless, cruel, unmerciful, remorseless: The novel
is about the relentless horde of Mongols that swept across
Europe in the 13th century. 2 non-stop, persistent, incessant,
unrelenting, unremitting, unstoppable, perpetual, unfaltering,
unfailing, unflagging, unrelieved, unabated, unrelieved,
unbroken, continual, continuous, ceaseless, constant, unceasing,
steady, habitual, regular: Won't you ever stop your relentless
nagging?
relevance n. relevancy, appropriateness, aptness, pertinence, bearing,
connection, affinity, tie-in, relation, significance,
suitability, suitableness, applicability, application,
applicableness: What you just said has no relevance whatsoever
to the issue under discussion.
relevant adj. pertinent, appropriate, apt, related, relative,
significant, suited, applicable, fitting, proper, germane, akin,
allied, associated, apposite, to the point: Alan's suggestion
is not strictly relevant to our plans.
reliable adj. dependable, trustworthy, honest, trusty, trusted,
principled, conscientious, punctilious, honourable, credible,
believable, safe, sure, certain, secure, sound, responsible,
predictable, stable, unfailing, infallible, reputable: Would a
reliable employee like Susan abscond with the money?
reliance n. confidence, trust, faith, dependence: You may be placing
too much reliance on the smoke alarm.
relic n. 1 memento, keepsake, memorial, remembrance, souvenir,
heirloom, token, artefact or artifact: It has been argued again
and again that the Turin shroud, though old, is not a genuine
relic of Christ. 2 remains; fragment, trace, scrap, shard or
sherd, remnant: Deep in the jungle, archaeologists unearthed
relics of a previously unknown civilization.
relief n. 1 ease, easing, abatement, easement, deliverance, remedy,
redress, alleviation, release, remission, assuagement,
liberation, recess: We would all welcome relief from this