The one who conceals hatred has lying lips, and whoever utters slander is a fool.
Proverbs 10:18

Speech and silence can both be wicked, depending on the context.
-Concealing hatred might be better than speaking it, depending on whether it is concealing one's own hatred or that of someone else.
-To conceal the actual hateful acts of another person may be to become party to those words.
-To conceal one's own heart-hatred of another person might be dishonest, but it's usually better than speaking it aloud or letting it come out through hateful actions, for example in making false accusations.