infra-, infero-, infer-

Part of a modern combining form of Latin inferus "low" (as in inferior), used in scientific terms (primarily in Zoology) to designate parts situated low down or on the under side; as infero-anterior, situated below and in front; infero-frontal, in the lower part of the forehead; infero-lateral, below and on one side; infero-median, in the middle of the under side; infero-posterior, below and behind.

A defender or champion of the underdog. (Coined by Christopher Morley, 1930).