adj, noun ·Rare ·Advanced level

Definitions

Noun

1. 1
   A mammal having no placenta. archaic

Adjective

1. 1
   Not having a placenta (said of e.g. marsupials and monotremes). archaic, not-comparable

Etymology

From im- + placental.

Data sourced from Wiktionary, WordNet, CMU, and other open linguistic databases. Updated March 2026.