indole

Short definition from Wiktionary

Noun

1. 1
   An organic compound, C₈H₇N, found in coal tar, and produced in the gut by the bacterial decomposition of tryptophan; it is an aromatic bicyclic heterocycle having a benzene ring fused with a pyrrole ring; indole and its derivatives occur widely in nature and have many industrial applications.
2. 2
   Any of the derivatives of indole.

Adjective

1. 1
   guileless