rigorous, a. [severe], [stringent], [strict], [unyielding]; inclement, [severe].
rile, v. (Colloq.) [roil]; [anger], [vex], [offend].
rill, n. streamlet, [rivulet], runnel, [brook].
rily, a. (Colloq.) [roily], turbid.
rim, n. [brim], [margin], [edge], [brink], verge, [border]; felly (rim of a wheel).
rime, n. hoarfrost.
rind, n. [skin], [peel]. Antonym: pulp.
ring, v. [sound], [resound], [reverberate]; toll, knell, [chime], ding, tinkle, clang.
ring, n. [circle], hoop; grommet, gimmal, terret, manilla, lute; annulation, annulet. Associated words: annular, annularity, annulate, signet, dactyliology, dactylioglyphy, dactylioglyph, [cameo], [intaglio], lapidary, lapidist, [posy].