A repugnantibus, lat. repugnans “contradictory; resistant, contrary, incompatible”.
Repugnant meaning “disgusting” is also derived from this source, but the argument a repugnantibus is not the “argument of disgust”, S. Emotions.
The meaning of Lat. repugnans in a repugnantibus is closer to “revolting, unacceptable”, the second meaning of Eng. repugnant.

1. In Cicero’s Topica, the a repugnantibus argument is based on logically “contradictory” things (Cicero, Top, XII, 53; p. 420).
In her translation of Boethius, Stump translates a repugnantibus as “from incompatible” (Boethius Top. p. 64), S. Contradiction; Opposites.

This logical a repugnantibus argument is based on contradiction, whereas the ad incommodum argument involves consequences subjectively unacceptable to the speaker, either from a material or a moral point of view, S. Pragmatic argument.

2. Bossuet defines the a repugnantibus argument as a contradiction between act and speech: “your conduct does not suit your speech” ([1677], p. 140), which corresponds to the third type of ad hominem argument, S. Ad hominem.