The phrase "has a handle on" typically refers to a person who has a good understanding or control of a situation or topic. However, there are many antonyms for this phrase that suggest a lack of understanding or control. Some examples of antonyms or phrases that convey the opposite meaning include, "struggling with," "clueless about," "in the dark," "ignorant of," "unfamiliar with," "out of touch with," "unsure of," or "unacquainted with." These phrases can be used to describe someone who feels lost, confused or lacks the knowledge and skills required to handle a particular situation effectively.