Bedeutung von “cast-iron” — Learner’s Dictionary

cast-iron

adjective us uk /ˈkɑːstˌaɪən/
NO DOUBT [ always before noun ]

able to be trusted completely, or impossible to doubt:

I need a cast-iron guarantee that the work will be finished on time.
METAL

made of cast iron

(Definition von “cast-iron adjective” aus dem Cambridge Learner's Dictionary © Cambridge University Press)