From Longman Dictionary of Contemporary Englishassailantas‧sai‧lant /əˈseɪlənt/ noun [countable] formal ATTACKsomeone who attacks another person SYN attacker
Examples from the Corpus
assailant• He believed that with such experience she would not have resisted the orders of her assailant.• The lieutenant kicked and punched her assailants but was overpowered.• Compounding all this is the fear that the ordeal is not yet over and that her assailants may return to kill her.• Tiny though she was compared with her assailant, she fought like a wildcat.• The doctoral student was apparently attempting to change a flat tire when his assailant struck.• It flings its fine hairs in the face of the assailant, in a dense cloud.• Sleep came to him like an unseen assailant. 