negative

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

• adjective Expressing, containing, or consisting of a negation, refusal, or denial.
• adjective Indicating opposition or resistance.
• adjective Lacking positive or constructive features, especially.
• adjective Unpleasant; disagreeable.
• adjective Gloomy; pessimistic.
• adjective Unfavorable or detrimental.
• adjective Hostile or disparaging; malicious.
• adjective Medicine Not indicating the presence of a particular disease, condition, or organism.
• adjective Logic Designating a proposition that denies agreement between a subject and its predicate.
• adjective Of or relating to a quantity less than zero.
• adjective Of or relating to the sign (−).
• adjective Of or relating to a quantity to be subtracted from another.
• adjective Of or relating to a quantity, number, angle, velocity, or direction in a sense opposite to another of the same magnitude indicated or understood to be positive.
• adjective Of or relating to an electric charge of the same sign as that of an electron, indicated by the symbol (−).
• adjective Of or relating to a body that has more electrons than protons.
• adjective Chemistry Of or relating to an ion, the anion, that is attracted to a positive electrode.
• adjective Biology Moving or turning away from a stimulus, such as light.
• noun A statement or act indicating or expressing a contradiction, denial, or refusal.
• noun A statement or act that is highly critical of another or of others.
• noun Something that lacks all positive, affirmative, or encouraging features; an element that is the counterpoint of the positive.
• noun A feature or characteristic that is not deemed positive, affirmative, or desirable.
• noun Grammar A word or part of a word, such as no, not, or non-, that indicates negation.
• noun The side in a debate that contradicts or opposes the question being debated.
• noun An image in which the light areas of the object rendered appear dark and the dark areas appear light.
• noun A film, plate, or other photographic material containing such an image.
• noun Mathematics A negative quantity.
• transitive verb To refuse to approve; veto.
• transitive verb To deny; contradict.
• transitive verb To demonstrate to be false; disprove.
• transitive verb To counteract or neutralize.

from The Century Dictionary.

• To deny, as a statement or proposition; affirm the contradictory of; contradict; negate.
• To disprove; prove the contrary of.
• To refuse assent to; refuse to enact or sanction; veto.
• In grammar, to modify by a negative particle: alter by the substitution of a negative for a positive word.
• Expressing or containing denial or negation: opposed to affirmative: as, a negative proposition.
• Expressing or containing refusal; containing or implying the answer “No” to a request: as, a negative answer.
• Characterized by the omission or absence of that which is affirmative or positive: as, a negative attitude; negative goodness.
• Having the power of stopping or restraining by refusing assent or concurrence; imposing a veto.
• In photography, showing the lights and shades in nature exactly reversed: as, a negative picture; a negative plate. See II., 5.
• Measured or reckoned in the opposite direction to that which is considered as positive; neutralizing the positive: as, a debt is negative property.
• Electricity developed by friction on resinous substances, as by rubbing sealing-wax with silk or flannel; resinous electricity.
• noun A proposition expressing a negation; a negative proposition.
• noun A term or word which expresses negation or denial.
• noun The right or power of refusing assent; a veto; also, the power of preventing.
• noun That side of a question which denies what the opposite side affirms; also, a decision or an answer expressive of negation: as, the question was determined in the negative.