Causing wry amusement (6)
(Other definitions for ironic that I've seen before include "Paradoxical, contradictory" , "'Wry, incongruous (6)'" , "Describes a statement that says the opposite of what is clearly the case" , "Paradoxically amusing" , "Perversely humorous" .)
(Other definitions for ironical that I've seen before include "Involving satire" , "skittish" , "With humorously opposite meaning" , "Incongruous or wry" , "Socratic method of discussion, professing ignorance" .)