Source: Tafsir al-Ahlam al-Kabir (Ibn Sirin)
The whip in a dream is a gossiping man who divides people. Striking with it indicates admonition.
Source: Ta'tir al-Anam fi Ta'bir al-Manam (Al-Nabulsi)
The whip indicates ugly speech. Whoever sees himself being whipped will hear words that harm him.
Source: Al-Isharat fi Ilm al-Ibarat (Ibn Shahin)
The whip is interpreted as a bad man. Whoever sees himself strike with it is harming people with his tongue.