Sluttishly is an adjective that describes someone or something that behaves or appears in an irresponsible or promiscuous manner. There are several synonymous words that can be used to replace sluttishly, including lewdly, licentiously, wantonly, dissolutely and salaciously. These words all imply a disregard for moral standards or decency, and suggest a level of promiscuity or sexual impropriety. Other synonyms for sluttishly include provocatively, indecently, immodestly, and brazenly. Regardless of which synonym is used, the underlying tone is typically one of disdain or disapproval, implying that the person or behavior being described is inappropriate or unacceptable.