文身

Xinhua notes 文身 as a pre-modern ethnographic practice of body decoration, documented in China among 高山, 黎, 独龙, 傣 and other southern peoples — figures, totems, 八卦 diagrams marking identity, belief, or beauty. The character 文 itself originally depicted a body with markings.

usage

文身 is the older written form; 纹身 (with 纟 'thread') is the common modern variant. CC-CEDICT lists 纹身 as a variant of 文身. Both are correct; mainland signage more often uses 纹身.