Castellate is a term used to describe something that resembles a castle or fortress. Here are some synonyms that you can use instead of castellate: battlemented, crenellated, embattled, fortified, turreted, fortified, citadel-like, bastioned, castled, and towered. These words can be used interchangeably when you want to convey an idea related to castles, strongholds, and fortresses. For instance, you can use the phrase "the crenellated walls of the fortress" instead of "the castellated walls of the castle." Similarly, you can use "a fortified stronghold" when you mean castellate. These synonyms are especially useful when describing a medieval setting or a location that has been protected and fortified.