define transpiring.
verb (used without object), transpired, transpiring. 1. to occur; happen; take place. 2. to emit or give off waste matter, watery vapor, etc., through the surface, as of the body or of leaves. 3. to escape, as moisture or odor, through or as if through pores. 4. to be revealed or become known. verb (used with object), transpired, transpiring.