can't make heads or tails (out) of (someone or something)

can't make heads or tails (out) of (someone or something)

Cannot understand someone or something at all; cannot make any sense of someone or something. I've been working with the new software for hours, but I still can't make heads or tails out of it. I can't make heads or tails of that new guy in accounting. Sometimes, he's really friendly, and then other times he acts like he's never met me before.See also: head, make, of, tail

can't make heads or tails (out) of someone or something

Fig. [to be] unable to understand someone or something. (Also with cannot.) John is so strange. I can't make heads or tails of him. Do this report again. I can't make heads or tails out of it.See also: head, make, of, tail

can't make head or tail of

Also can't make heads or tails of. Fail to understand, be quite confused about, as in I can't make head or tail of these directions. A version of this term dates back to Roman times, when Cicero wrote Ne caput nec pedes ("neither head nor feet") to describe confusion. In the current idiom the precise allusion is unclear: head and tail may mean top and bottom, beginning and end, or the two sides of a coin. [Second half of 1600s] See also: head, make, of, tail

cannot make head or tail of something

or

cannot make head nor tail of something

mainly BRITISHIf you cannot make head or tail of something or cannot make head nor tail of it, you cannot understand it at all. I couldn't make head or tail of the instructions. They couldn't make head nor tail of the new computer system.See also: cannot, head, make, of, something, tail