hard as a rock

*hard as a rock

and *hard as stone

very hard. (*Also: as ∼.) This cake is as hard as a rock! I can't drive a nail into this wood. It's hard as stone.

Name	Pronounced	Usage
Polona	-	Slovene
Lyon	['laiən]
Katharine	['kæθərin]
Kaapo	KAH:-po	Finnish
RiagÁN	-	Irish
Ranko	-	Serbian, Croatian