Longman Dictionary of Contemporary English - ironic

also ironical ~ adj 1 using words that are the opposite of what you really mean, especially in a joking way, or to show that you are annoyed  (As the rain lashed down, my mother's one ironic comment was)  ("An ideal day for a wedding.")  (- compare sarcastic) 2 an ironic situation is one in which something strange and unexpected happens, especially in a way that seems amusing  (Your car was stolen at the police station! How ironic!)