Wiktionary
a. consistent and dependable in one's behaviour or performance
WordNet
adj. consistent in performance or behavior; "dependable in one's habits"; "a steady-going family man" [syn: dependable, steady-going]
Usage examples of "rock-steady".
After he had gained more than mere grudging attention from the gun captains, Sir Peter had them gather around closer and, with fingers that were big and work-stained and scarred, but still sure and rock-steady, he rapidly dismantled a brace of the friction primers and showed all of them the very simple works.
The corkscrewing and rolling gradually eased and ceased altogether, so did the creaking in the superstructure and the San Andreas, on an approximately south-west course, was almost rock-steady in the water.
A slight pitching disturbed the previous rock-steady motion, sign that the craft was in the grip of powers even greater than the technics she had brought with her from the Domination's timeline.