This is Sam’s tattoo from Mark Z. Danielewski’s House of Leaves:
The main character, Johnny Truant, strings these seemingly random words: Known. Some. Call. Is. Air. Am. and follows it with “Incoherent? Yes. Entirely without meaning? I’m afraid not.”
The assortment of words is actually phonetic Latin for “Non sum qualis eram.” or “I am not what I once was.”
When I first read the passage, I thought it was just a clever ploy by the author, but as time went on and I got older, I realized how much the quote meant to me. Growing up, I realized I was a completely different person than who I thought I was. The only natural thing to do was to express it with something permanent and unchanging.