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.

• Making resistance; resisting.
• noun One who or that which resists.
• noun Same as resist, 2.
• 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.

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