Suicide Squad: Decoding All 16 Of Jared Leto's Joker Tattoos
11. The Stabbed Bat-Logo
The imagery here pretty much speaks for itself: the Joker has stabbed Batman through the heart - presumably through killing Jason Todd - and it generally serves as a mark of his mantra and desire to kill the Batman.
But more specifically, the stabbed Bat is an Easter Egg, referring back to The Dark Knight Returns. In the culmination of that story, the Joker and Batman meet in a bloody battle that eventually sees the former perish (by his own hand); during the fight the Joker repeatedly stabs Batman in the stomach.
10. Hand Smile
Another blank space, another smile - this time a more narrow one with thicker lips that are parted rather than a drawn, tight grin.
This one is more like The Killing Joke smile - it's a fairly simple reference, rather than being steeped in the character's personal history.