thrust - A sudden or violent lunge with a pointed weapon or a bodily part
In the wrestling competition, Jerry's opponent had him pinned down, but with a strong thrust of his arms, Jerry pushed this opponent off of him, and then had his opponent pinned down instead.
arbitrary - Based on random choice or personal whim, rather than any reason or system
She felt that when the judges chose her competitor as winner of the debate, that the decision was totally arbitrary, and didn't recognize how well she had really done.
