The Collaborative International Dictionary of English v.0.48:

Wroth \Wroth\, a. [OE. wroth, wrap, AS. wr[=a][eth] wroth,
   crooked, bad; akin to wr[imac][eth]an to writhe, and to OS.
   wr[=e][eth]angry, D. wreed cruel, OHG. reid twisted, Icel.
   rei[eth]r angry, Dan. & Sw. vred. See Writhe, and cf.
   Wrath.]
   Full of wrath; angry; incensed; much exasperated; wrathful.
   "Wroth to see his kingdom fail." --Milton.
   [1913 Webster]

         Revel and truth as in a low degree,
         They be full wroth [i. e., at enmity] all day.
                                                  --Chaucer.
   [1913 Webster]

         Cain was very wroth, and his countenance fell. --Gen.
                                                  iv. 5.
   [1913 Webster]

WordNet (r) 3.0 (2006):

wroth
    adj 1: vehemently incensed and condemnatory; "they trembled
           before the wrathful queen"; "but wroth as he was, a short
           struggle ended in reconciliation" [syn: wrathful,
           wroth, wrothful]

Moby Thesaurus II by Grady Ward, 1.0:

21 Moby Thesaurus words for "wroth":
   angered, angry, browned-off, cross, heated, incensed, indignant,
   irate, ireful, livid, mad, pissed, pissed-off, riled up, sore,
   ticked off, waxy, worked up, wrathful, wrathy, wrought-up