Splitting hairs is an idiom that means to make a distinction between two things that are very similar, often in an overly critical or nitpicky way. The crossword solutions for this term include DIFFERENTIATE (13 letters), NITPICKED (9 letters), QUIBBLE (7 letters), CAVIL (5 letters), PART (4 letters), PARTED (6 letters), CAVILED (7 letters), NITPICK (7 letters), and DISCRIMINATE (12 letters). All of these words describe the act of making small distinctions between two similar things, often in an overly critical or nitpicky way.