diff --git a/share/functions/__fish_whatis.fish b/share/functions/__fish_whatis.fish
new file mode 100644
index 000000000..57d8f530d
--- /dev/null
+++ b/share/functions/__fish_whatis.fish
@@ -0,0 +1,21 @@
+# uses `whatis` if available to describe a command
+
+function __fish_whatis
+	set -l cmd $argv[1]
+	set -l fallback
+	if set -q argv[2]
+		set fallback $argv[2]
+	end
+
+	set -l description (whatis $cmd 2>/dev/null | string replace -r '.*? - ' '')[1]
+	if not string match -qr -- "$description" "."
+		printf '%s\n' $description
+		return 0
+	else if not string match -q -- "$fallback" ""
+		printf '%s\n' $fallback
+		return 0
+	else
+		return 1
+	end
+end
+