turun, see *turúna
Quenya
*turúna
mastered
turúna
adjective. mastered
turun
turun
turu-
master, defeat, have victory over
turu- (1) vb. "master, defeat, have victory over" (PE17:113, not clearly said to be Quenya, but the Q name Turucundo "Victory-prince" is listed immediately afterwards). Compare tur-; cf. also *turúna.
-na
no longer part of verbal conjugation
-na (4), ending used to form passive participles as well as some adjectives and nouns; see -ina. According to PE17:68, the ending -na was "no longer part of verbal conjugation"; the derived words are thus considered independent adjectives (sometimes nouns) rather than regularly derived passive participles, the obvious etymological connection to certain verbal stems notwithstanding. Where adding the ending to a root would produce the combinations tn, pn, kn (cn), metathesis occurs to produce nt, (np >) mp, nc, as in nanca *"slain" for older ¤ndakna, or hampa "restrained, delayed, kept" vs. the root KHAP "retain, keep, detain". Following -l, the suffix -na turns into -da, as in yulda "draught, the amount drunk" for older yulna (this being an example of a noun being derived with this ending, though Tolkien might also explain yulda as containing a distinct ending -da [q.v.] denoting the result of a verbal action). The word *turúna "mastered" (q.v., only attested in elided form turún) would seem to be a passive participle formed from the verb turu- "master" (PE17:113), suggesting that in the case of U-stem verbs, their final -u is lengthened to ú when -na is added.
*turúna passive participle "mastered", only attested attested in the elided form turún' (UT:138, apparently incomplete spelling turun in Silm ch. 21). The form may be understood as the passive participle of the verb turu- "master, defeat, have victory over" (PE17:113), the sole available example of a U-stem verb appearing in such a participle form. Compare -na #4.