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.
If you're unsure what to feed your little one, consider feeding the kitty some goat's milk. Goat's milk has less lactose than cow milk. Whole cow's milk isn't the best idea for nursing kittens because they are lactose intolerant; diarrhea's a likely result.