Antonyms of adj undecomposed

1 sense of undecomposed

Sense 1
good, undecomposed, unspoiled, unspoilt -- (not left to spoil; "the meat is still good")

INDIRECT (VIA fresh) -> stale -- (lacking freshness, palatability, or showing deterioration from age; "stale bread"; "the beer was stale")

Similarity of adj undecomposed

1 sense of undecomposed

Sense 1
good, undecomposed, unspoiled, unspoilt -- (not left to spoil; "the meat is still good")
       => fresh (vs. stale) -- (recently made, produced, or harvested; "fresh bread"; "a fresh scent"; "fresh lettuce")