sanguis.

From Proto-Italic *sangwens, with the first syllable san- from Proto-Indo-European *h₁sh₂-én-, the oblique stem of *h₁ésh₂r̥ n (“blood”), whence also saniēs (“ichor; ulcer”) via suffixation. Old Latin assyr /aser /ascer (found in glosses only) likely reflects the nominative of the original paradigm. Later sanguĭs occurred as a regularization of sanguīs by analogy with the third-declension adjectival suffix -is. However, there is no consensus on whether the original nominative form was sanguīs m or sanguen n, but the development Proto-Italic *sangwens > Old Latin *sanguins > Classical Latin sanguīs seems most likely, since the expected Classical reflex of Old Latin **sanguens would be **sanguēs. Rather, sanguen can be explained as a later reshaping on the analogy of unguen, inguen etc. Cognate to Hittite 𒂊𒌍𒄯 (ēšḫar), Sanskrit असृज् (ásṛj), Ancient Greek ἔαρ (éar), Old Armenian արիւն (ariwn). Pittau also suggests Etruscan 𐌔𐌀𐌍𐌗𐌖𐌍𐌄𐌕𐌀 (sanxuneta, “the sanguinary”, with the enclitic article -𐌕𐌀 (-ta)) as a possible cognate.