* Formal: "Despite their professional rivalry, they maintained a carefully constructed facade of friendship, making them more frenemies than colleagues."
* Informal: "Sarah and I are frenemies – we love to gossip about each other, but we also secretly admire each other's style."
* Humorous: "My frenemy told me I looked great today... in a 'you're getting old' kind of way."
Remember: "Frenemy" is a slang term and might not be appropriate for all situations. Consider your audience and the tone you want to convey.