General:
* Promontory: This is a very common and accurate synonym.
* Cape: Often used for particularly prominent headlands.
* Point: A more general term for a landform that juts out, but less specific than headland.
* Spur: Suggests a smaller, more pointed headland.
More specific:
* Cliff: If the headland is characterized by steep cliffs.
* Bluff: Similar to cliff, but often less dramatic.
* Nose: Suggests a rounded headland.
* Foreland: A more technical term, emphasizes the jutting out aspect.
The best synonym for "headland" depends on the specific context and the characteristics of the particular headland you're describing.