Unbeatable means so good that nothing can better it. An unbeatable price, an unbeatable team, unbeatable value.
In advertising it is a claim about price and is usually hedged in small print, since nothing is literally unbeatable for long. Of a team it means unbeaten in practice rather than in principle, and every unbeatable side eventually loses.
1adjectiveunbeatableSo good that nothing can better it.
“For fresh fish, that little café by the harbour is unbeatable.”
unbeatable is a quality.
Un- plus beatable, from beat, from Old English beatan, to strike.
Middle English
beten
English
beat
English, today
unbeatable
From un- + beat + -able. beatable is a back-formation. beat comes from Middle English beten. Middle English beten, from Old English bēatan (“to beat, pound, strike, lash, dash, thrust, hurt, injure”), from Proto-West Germanic bautan, from Proto-Germanic bautaną (“to push, strike”). 2
Etymology from Wiktionary, CC BY-SA