rock-solid

adjective
rock-sol·​id | \ ˈräk-ˈsä-ləd How to pronounce rock-solid (audio) \
variants: or rock solid

Definition of rock-solid

: completely or perfectly solid (as because of great strength or dependability) supported by a rock-solid foundation She has a rock-solid reputation. Their relationship was rock solid. … she moved in a an artificial world without ever losing her rock-solid integrity.— Walter Clemons He is right to imply that the political structure is a little shaky—it was a myth that it was ever rock solid.— Xan Smiley

First Known Use of rock-solid

1871, in the meaning defined above

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