"Native" refers to something or someone that originates from a particular place, especially where they were born. The opposite would be "alien," which refers to something foreign or from another place. Therefore, "alien" is the correct antonym.

Opposite words: Exotic, Alien, Expatriate, Immigrant, Peregrination, Adventitious.

"Specious" refers to something that appears to be true or right, but is actually false or misleading. The opposite of "specious" would be something that is genuinely true, or "valid." "Valid" describes something that is based on sound reasoning or truth, making it the correct antonym.

Opposite words: Valid, Straightforward, Aboveboard, Candid, Forthright, Unfeigned, Outgiving, Naïve.

"Gambol" means to run or jump about playfully, often with joy or abandon. The opposite of this would be "plod," which refers to walking heavily or slowly, lacking energy or playfulness. Thus, "plod" is the correct antonym.

Opposite words: Work, Labor, Plod.

"Stability" refers to a state of being steady and reliable. Inconsistency means a lack of stability or reliability.

Opposite words: Incompatibility, Inconsistency, Impropriety, Hectic, Keyed, Groggy, labile. 

"Mollify" means to calm or soothe someone's anger. Ire refers to intense anger or rage, which is the opposite of mollifying.

Opposite words: Ire, Anger, Infuriate, Inflame, Outrage, Enrage.

"Orient" means to familiarize or guide someone in a new environment or situation. Confuse is the opposite, meaning to make someone unclear or disoriented.

Opposite Words: Unknown, Impracticable, Rummy, Weird.

"Whimsical" refers to being impulsive, playful, or fanciful in an unpredictable way. Predictable is the opposite, meaning something that can be foreseen or expected.

Opposite words: Pragmatic, Equable, Sober, Predictable.

"Celebrated" refers to someone who is famous or well-known. Unknown is the opposite, meaning someone who is not famous or recognized.

Opposite words: Unknown, Undistinguished.

"Applaud" means to express approval or praise. Criticize is the opposite, meaning to express disapproval or point out faults.

Opposite words: Slam, Pan, Blame, Disparage, Admonish, Reproach, Vilify, Flatter.

An ally is a person or group that supports another, while an adversary is an opponent or enemy.

Opposite words: Adversary, Detractor, Foe, Rival.