battleaxe
鉞 centers on a large, bladed weapon used in battle: a battleaxe.
鉞 combines 金 (metal) with 戉, which is an ancient pictograph of a battleaxe and also provides the sound. Together they specify a metal battleaxe.
The left side 金 means metal, and the right side 戉 looks like a blade on a long handle. Picture a heavy metal battleaxe ready for combat.
For エツ, imagine an ancient warrior named Etsu swinging a metal battleaxe: Etsu -> エツ.