Antonyms of adj penniless

1 sense of penniless

Sense 1
hard up, impecunious, in straitened circumstances (predicate), penniless, penurious, pinched -- (not having enough money to pay for necessities)

INDIRECT (VIA poor) -> rich -- (possessing material wealth; "her father is extremely rich"; "many fond hopes are pinned on rich uncles")

Similarity of adj penniless

1 sense of penniless

Sense 1
hard up, impecunious, in straitened circumstances (predicate), penniless, penurious, pinched -- (not having enough money to pay for necessities)
       => poor (vs. rich) -- (having little money or few possessions; "deplored the gap between rich and poor countries"; "the proverbial poor artist living in a garret")