Scimitar! Since they are both curved. Cutlasses are shorter and heavier, but same deal basically
...though rapier is most similar to a cutlass.
In what way? Rapiers are long, straight, narrow-bladed thrusting weapons, while cutlasses are shorter, curved, broad-bladed slashing weapons. I think trancejeremy nailed it, TBH.
I might have had rapier and cutlass swapped in my head. I have some knowledge, but am no swordsmith, nor sword expert of any kind.

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.