"Tongue-in-cheek" is a phrase used to describe a statement that is not meant to be taken seriously, typically meant as a joke or a sarcastic remark. However, there are many other words that can be used interchangeably with this phrase. Some synonyms for "tongue-in-cheek" include "facetious," "ironic," "witty," "sarcastic," "satirical," and "humorous." These words convey a lighthearted or playful tone that is characteristic of a tongue-in-cheek remark. While each of these synonyms has their own unique nuances, they all share the same definition of being a humorous comment made in an ironic or playful way.