bridle
靮 centers on the leather straps used to control a horse: a bridle.
靮 combines 革 (leather) with 勺, which likely contributes a phonetic element. The character specifically denotes a leather bridle.
The left side 革 means leather, and the right side 勺 looks like a ladle or a curved hook. Imagine a leather strap shaped like a ladle's handle, used to guide a horse: that's a bridle.
For テキ, picture a horse wearing a leather bridle, and you give it a gentle 'tek' sound to steer it: tek -> テキ.