etiolate

from The American Heritage® Dictionary of the English Language, 5th Edition.

• intransitive verb Botany To cause (a plant) to develop without chlorophyll by preventing exposure to sunlight.
• intransitive verb To cause to appear pale and sickly.
• intransitive verb To make weak by stunting the growth or development of.
• intransitive verb To become blanched or whitened, as when grown without sunlight.

from The Century Dictionary.

• To grow white from absence of the normal amount of coloring matter, as the leaves or stalks of plants; be whitened by exclusion of the light of the sun, as plants: sometimes, in pathology, said of persons.
• To blanch; whiten by exclusion of the sun's rays or by disease.
• Synonyms Blanch, etc. See whiten.
• Also etiolize.

from the GNU version of the Collaborative International Dictionary of English.

• transitive verb To blanch; to bleach; to whiten by depriving of the sun's rays.
• transitive verb (Med.) To cause to grow pale by disease or absence of light.
• intransitive verb To become white or whiter; to be whitened or blanched by excluding the light of the sun, as, plants.
• intransitive verb (Med.) To become pale through disease or absence of light.
• adjective Having a blanched or faded appearance, as birds inhabiting desert regions.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• verb To make pale through lack of light, especially of a plant.
• verb To make a person pale and sickly-looking.
• adjective etiolated

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• verb bleach and alter the natural development of (a green plant) by excluding sunlight
• adjective (especially of plants) developed without chlorophyll by being deprived of light
• verb make weak by stunting the growth or development of
• verb make pale or sickly