3. Odor, smell, scent, stench all refer to sensations perceived through the nose by the olfactory nerves. Odor and smell in literal contexts are often interchangeable. Figuratively, odor also usually occurs in positive contexts: the odor of sanctity. Smell is the most general and neutral of these two terms, deriving connotation generally from the context in which it is used: the tempting smell of fresh-baked bread; the rank smell of rotting vegetation. In figurative contexts smell may be either positive or negative: the sweet smell of success; a strong smell of duplicity pervading the affair. Scent refers either to delicate and pleasing aromas or to faint, barely perceptible smells: the scent of lilacs on the soft spring breeze; deer alarmed by the scent of man. Stench is strongly negative, referring both literally and figuratively to what is foul, sickening, or repulsive: the stench of rotting flesh; steeped in the stench of iniquity and treason.

Did you mean colorless?