Wordnet 3.0
ADJECTIVE (1)
1. 
 having no odor; 
- Example: "odorless gas"- Example: "odorless flowers"[syn: odorless, odourless, inodorous]
WordNet (r) 3.0 (2006):
odourless
    adj 1: having no odor; "odorless gas"; "odorless flowers" [syn:
           odorless, odourless, inodorous] [ant: odorous]