What term describes something that is menacing or threatening?

The term that describes something menacing or threatening is "ominous." This word is often used to convey a sense of foreboding or an indication that something bad is likely to happen. It captures the essence of an atmosphere or event that feels unsettling and suggests danger lurking beneath the surface.

In contrast, the other terms connote different meanings that do not align with the idea of menace or threat. For instance, "acquiescent" refers to a willing acceptance or passive agreement, which does not imply any form of threat. Similarly, "friendly" and "inviting" clearly indicate warmth and approachability, opposite of what is associated with something that is ominous. Thus, "ominous" stands out as the term that accurately reflects a sense of danger or the presence of a threat.