HAHA Views 8 meanings found HAHA is a slang abbreviation for “having a heart attack,” also appears in scientific literature as human anti‑human antibody, and names community groups for humanists, atheists and agnostics. Medical Health And Humor Associates Miscellaneous Hideous Artwork Has Award Human Anti Human Antibody Having A Heart Attack Community Humanists Atheists Heretics And Agnostics Harrisburg Area Homeschoolers Association Academic & Science Honorary After Hours Activities Sports Huntsville Amateur Hockey Association