Ludus is playful or uncommitted love, primarily shown by opposite gender couples. It can involve activities such as teasing and dancing, or more overt flirting, seducing, and conjugating, or pairing off with one another. The focus is on fun, and sometimes also on [oneupmanship], with no strings attached. Ludus relationships are casual, undemanding, and uncomplicated but, for all that, can be very long-lasting. Ludus works best when both parties are mature and self-sufficient. Problems arise when one party mistakes ludus for eros, whereas ludus is in fact much more compatible with philia.
---Taken from the Psychology Today blog, by Neel Burton, M.D. Published June 26, 2016. Updated June 19, 2019. Edited for brevity and clarity. Bold text added.