From Longman Dictionary of Contemporary Englishrock-solidˌrock-ˈsolid, rock solid adjective 1 DEPEND ON/RELY ONrock-solid things can be depended on and trusted not to change a rock-solid guarantee2 STRONG OBJECTvery hard and not likely to break
Examples from the Corpus
rock-solid• rock-solid commitment• Full-back Lyon also kept himself in contention for the tour with some exciting running and rock-solid defence.• Victory came courtesy of rock-solid defender Richard Smith's one mistake eight minutes from time.• The rock-solid fuel supply with rock-solid benefits.• And even if you think you are in a rock-solid job, it could still happen to you.• Francis noted that strong profit margins and a committed, rock-solid management team were the key elements for a successful start-up.• Based on my limited sampling, 1994 is a rock-solid vintage. 