Tatted up from head to toe, guess you can call me a mark man
A large portion of the upper-epidermis is covered in the semmi-permanent ink of a tattoo. He is saying because he is covered in ink marks to call him a “Marksmen”.
Also notice that this punchline refers to the line where he mentions “cop guns”, as Wayne also has guns and claims that he’ll “shoot you up in your database”, though being a good Marksman (a sharpshooter)!
To help improve the meaning of these lyrics, visit "Mercy" by Lil Wayne (Ft. Nicki Minaj) Lyrics and leave a comment on the lyrics box