What is the meaning of Donn?

to do

Used in the preterite with a following infinitive to form the paraphrastic preterite.

Used in the subjunctive with a following infinitive to form the conditional tense.

brown, tawny, dun

hazel

chestnut

chief, lord, noble

lordship, chieftainship

princely, noble

theft, stolen property

then, at that time

brown

brown-haired, brunette

made of hard brown timber

strong, solid

used as intensifying term

brown

brown animal

hard brown timber

alternative form of donnaigh (“brown; tan, rust”)

noble, prince

alternative form of dronn (“hump; camber”)

seemingly, by appearance

brown

brown-haired, brunette

Source: wiktionary.org