- [ ] racing
- [ ] racket
- [ ] radar
- [ ] radiate
- [ ] radical
- [ ] radioactive
- [x] radius
- [ ] raft
- [ ] rage
- [x] rainbow
- [x] rainfall
- [ ] raise the roof
- [ ] rally
- [ ] ranch
- [x] random
- [x] range
- [x] rank
- [x] rare
- [ ] rash
- [ ] ratify
- [x] ratio
- [ ] ration
- [ ] rational
- [ ] rattle
- [ ] raw
- [x] ray
- [ ] rayon
- [ ] readily
- [ ] realm
- [ ] rear
- [x] reason
- [ ] rebel
- [x] recall
- [ ] receptacle
- [ ] reception
- [ ] receptor
- [ ] recession
- [ ] recipe
- [ ] reckless
- [x] recognize
- [x] recommend
- [x] recover
- [ ] recreation
- [ ] recruit
- [x] rectangle
- [x] recycle
- [ ] reddish
- [ ] reef
- [ ] refer
- [x] refer to
- [x] reference
- [ ] refine
- [ ] refined
- [x] reflect
- [ ] reform
- [ ] refreshing
- [ ] refrigerate
- [ ] refund
- [ ] refurbish
- [x] regardless
- [ ] regardless of
- [x] regenerate
- [ ] region
- [x] register
- [x] regular
- [x] regulate
- [ ] rehabilitate
- [ ] rehearse
- [x] reinforce
- [x] reject
- [ ] rejuvenate
- [x] relative
- [x] relatively
- [ ] relay
- [x] release
- [x] relevant
- [x] reliable
- [ ] relic
- [x] relief
- [x] relieve
- [ ] religion
- [ ] reluctant
- [x] rely on
- [ ] remainder
- [x] remains
- [x] remark
- [ ] remarkable
- [x] remind
- [ ] remnant
- [ ] remodel
- [x] remote
- [ ] removal
- [x] renaissance
- [x] render
- [x] renew
- [ ] renovate
- [ ] repel
- [ ] repertoire
- [ ] repertory
- [ ] repetition
- [ ] replenish
- [ ] replicate
- [ ] represent
- [ ] reproduce
- [ ] reptile
- [x] republic
- [x] repute
- [x] request
- [x] require
- [x] rescue
- [ ] resemble
- [ ] reserve
- [ ] reservoir
- [ ] reside
- [ ] resident
- [ ] residue
- [x] resin
- [x] resist
- [ ] resolve
- [ ] resonance
- [ ] resort
- [ ] resource
- [x] respect
- [ ] respective
- [x] respond
- [x] response
- [ ] responsible
- [x] restore
- [ ] restraint
- [ ] restrict
- [ ] restricted
- [ ] result from
- [x] result in
- [x] resume
- [ ] retail
- [ ] retain
- [ ] retreat
- [ ] retrieve
- [x] reveal
- [ ] revenue
- [ ] revere
- [x] reverse
- [ ] revert
- [ ] revise
- [ ] revitalize
- [ ] revival
- [ ] revolt
- [x] revolution
- [ ] reward
- [ ] rhinoceros
- [ ] rhyme
- [x] rhythm
- [x] ribbon
- [ ] ridge
- [x] ridiculous
- [ ] rigid
- [ ] rigor
- [ ] ripe
- [ ] rite
- [ ] ritual
- [ ] rival
- [ ] roam
- [x] robust
- [ ] rod
- [ ] rodent
- [ ] rodeo
- [ ] roe
- [x] roll
- [x] romantic
- [x] rotate
- [ ] rough
- [ ] roughly
- [ ] rub
- [ ] rudimentary
- [ ] rug
- [ ] rugged
- [x] ruin
- [ ] rumor
- [ ] run into
- [ ] run out of
- [ ] rupture
- [ ] rural
- [x] rust
- [ ] rustic