resistant

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

• adjective Capable of, offering, or showing resistance. Often used in combination.
• noun One that is resistant, especially a person active in a Resistance movement.

from The Century Dictionary.

• In botany, able to resist the attacks of parasites: applied to those plants which, because of some inherent property, are able to resist the attack of those parasites to which they are usually subject.
• Making resistance; resisting.
• noun One who or that which resists.
• noun Same as resist, 2.

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

• adjective Making resistance; resisting.

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

• noun A person who resists; especially a member of a resistance movement.
• noun A thing which resists.
• adjective That which makes resistance or offers opposition.
• adjective That which is not affected or overcome by a disease, drug, chemical or atmospheric agent, extreme of temperature, etc..
• adjective statistics Not greatly influenced by individual members of a sample.

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

• adjective able to tolerate environmental conditions or physiological stress
• adjective incapable of absorbing or mixing with
• adjective relating to or conferring immunity (to disease or infection)
• adjective impervious to being affected
• adjective disposed to or engaged in defiance of established authority