Act rudely at the checkout counter

• Tap on the shoulder, maybe
• Interrupt, as a news broadcast
• Annoy a fellow motorist, perhaps
• Interrupt with a shoulder tap
• Interrupt at a dance
• Stop from stepping, perhaps
• What ballroom stags do
• Not wait one's turn
• Change partners, in a way

Wiktionary Word definitions in Wiktionary
n. (context biochemistry English) A waxy polymer of hydroxy acids that is the main constituent of plant cuticle