Rapt :---> concealed.
Rarefied :---> made less dense.
Recalcitrant :---> obstinately stubborn, unruly.
Recant :---> disclaim or disavow
Reciprocal :---> reverse or opposite
Recluse :---> hermit, loner, disappointed in love.
Recondite :---> abstruse, profound, secret.
Recurrent :---> repeated, recurring.
Refractory :---> stubborn, unmanageable.
Refute :---> disprove.
Relegate :---> banish to an inferior position
Relevance :---> quality of being relevant
renaissance :---> interest on particular topic
Renal :---> Pertaining to kidneys
renounce :---> reject
Reprise :---> repeat, returning
Reproach :---> express disapproval or disappointment.
Reprobate :---> person hardened in sin
Reprove :---> admonish, rebuke
Repudiate :---> disown, disavow.
Rescind :---> cancel.
Resolution/resolve :---> determination.
Reticent :---> reserved, uncommunicative.
Retrospective :---> review
Reverent :---> respectful, worshipful.
Rupture :---> break