It means Buddhist wisdom. It also means the horned mask of a woman consumed by jealousy.

What a Japanese person actually thinks
Genuinely split. Anyone with a Buddhist frame reads 'wisdom'; anyone with a tattoo or theatre frame reads the mask. Since hannya masks are one of the most common Japanese tattoo motifs in the West, most readers will assume you meant the demon.

Meaning

Literally: (phonetic transcription of Sanskrit prajñā)
Actually: Transcendent wisdom in Buddhism — the 般若 of the Heart Sutra (般若心経). Separately and far more visibly, the name of the Noh mask depicting a woman transformed into a demon by jealousy and rage.

Scores

Naturalness●●●●●

Correct word with two well-established, very different meanings.

Coolness●●●●●

Two dense phonetic characters, striking to look at. The ambiguity is the whole story here.

Watch out

mediumIf you want the wisdom meaning, be aware most viewers will supply the mask. If you want the mask, most tattooers would draw it rather than write it.

Get this instead

智慧 chie
wisdom; Buddhist insight

The wisdom meaning with no demon attached. 慧 in particular is a beautiful character.

On skin

般若

Orientation: vertical

Mincho, vertical.