noun
helmet crest; plume; pompom
Refers to the decorative ornament attached to the front of a traditional Japanese helmet (兜).
戦国武将の兜には、立派な前立てが付いていた。
The helmets of Sengoku warlords had magnificent crests attached.
noun
figurehead; nominal leader
Used for a person who is nominally in charge but has little real power, or a front person for an organization.
彼は社長だが、実際はただの前立てに過ぎない。
He is the president, but in reality he is nothing more than a figurehead.
お飾り is a more general term for a decorative object or a person kept for appearance, while 前立て specifically evokes the image of a helmet crest or a nominal leader.
Compound of 前 (mae, 'front') and 立て (tate, 'standing thing'). Originally referred to the standing ornament on the front of a helmet, later extended metaphorically to a person who stands at the front as a nominal leader.