The text on the cup is meant to be the name 'Clint', but due to the handwriting or font style, it looks like a different offensive word at first glance. The humor comes from the accidental misinterpretation of the handwriting.
The meme humorously points out how the choice of font can drastically alter the perception of text, in this case turning an innocent sign for 'The Clift Forest Recreation Area' into an inappropriate phrase due to the font making the 'f' and 't' look like a 't'. The font causes the text to be misread, providing an unexpected and humorous effect.
Why Fonts Matter, 2022 edition. WELCOME TO 'THE CLIT' FOREST RECREATION AREA