White spade suit

It is the spade suit sign, drawn hollow. A spade is the black, leaf-shaped mark with a stem that labels one of the four suits in the standard deck used internationally: spades ♠, hearts ♥, diamonds ♦ and clubs ♣. Spades is the highest-ranking suit in bridge bidding, and on English-style decks the ace of spades is the deck's most decorated card.

Unicode encodes each suit both filled and outlined. On ordinary card faces spades are filled, and bridge and card-game text normally uses ♠ too, so a bare ♤ rarely means a card at all. Where you will actually meet it is as a text ornament: framing a nickname, dotting a bio, or lined up with its hollow siblings ♡ ♢ ♧ as a little decorative row.

Japanese and Korean input methods make it easy to reach. Japanese keyboards typically offer both ♠ and ♤ when you convert the typed word for spade, and Korean PC keyboards list ♤ in their symbol table, so for those users it is about as handy as a star. Sent on its own it carries no strong message: it reads as neutral decoration, much as ☆ does next to ★.

♤ or ♠: which one should I use?

♠ for cards; ♤ for decoration or a lighter look. They are two separate characters that mean the same suit. ♠ is the one card players, games and printers use, and it also has an emoji form, so it can appear as a colourful picture on phones. ♤ is text only and has no emoji form, so it keeps its outline look, which is why people pick it when they want something quieter than a solid black blob.

Because it is plain text, its exact shape, weight and size depend on the reader's font; a few older or minimal fonts have no outline suits at all and show a box instead. ♠ is the more common character, so it is less likely to go missing.