The OI word "crimthann" is glossed as "sinnach" (fox), but is
generally a proper name. I'm assuming that in this respect it is like
other proper names such as Art (= bear) and Tadg (= badger) which
preserve animal names that fell out of everyday use long ago, possibly
as a result of tabu avoidance.
Thurneysen (GOI p. 52) derives the word/name from "crem" (= wild
garlic), although he doesn't address the second element.
LEIA s.v. "cáer" says that "cáerthann" (= rowan tree) is made up of
"cáer" (= berry) plus -than / -then "comme d'autres noms d'arbres et
de plantations". This latter apparently comes from Pedersen, as given
in this entry for "fíntan" in DIL:
> a vineyard: gl. vinetum Sg 53 a 3 . A compd. of fín `wine ,' and
> tan `time ,' orig. used of space also, Ped. ii 14 ; of *ten, *tan
> `tree,' found as suff. inróstan, cairthen(n) and npr. Crimthann,
> Dergthenn, etc. KM Wortk. 19
> . Cf. Marstrander, Vidensk. Skr. II Hist.-fil. Kl. 8 , Kristiania .
1. Is Pedersen's derivation of -than from "tan" still accepted?
2. LEIA says that Thurneysen's etymology of "Crimthann" from "crem"
seems "aventurée au moins pour le nom commun signifiant « renard ».
Could garlic have come into a word for "fox" because of the animal's
musky odor (as in "sionnach ar bhréine") ?