Verbal irony is when what is said is the opposite of the literal meaning. One type of verbal irony is sarcasm, where the speaker says the opposite of what he or she means in order to show contempt or mock. Other types of verbal irony include overstatement (or exaggeration) and understatement.
Thanks for A2A. There are two excellent, well-informed answers here, so I'll just try to simplify. Dr. Falconer is of course correct; pre-weaning age (about 9 weeks or younger) kittens can drink cow's milk, or any milk. Neonates are not lactose intolerant; this develops gradually with age.
Knowing when to wean kittens benefits the kittens as well as the mother cat. As kittens grow, they require more nutrition. The mother cat will benefit because her body will no longer need to produce as much milk. Kittens will naturally begin the weaning process when they are four to five weeks old.