- reliable, esp financially reliable
from the former practice of coating the bottoms of ships with copper to prevent the timbers rotting
Examples from the Web for copper-bottomed
He'd find evidence of lung trouble in a copper-bottomed boiler if it wheezed letting off steam.Facts And Fictions Of Life
Helen H. Gardener
It's real, copper-bottomed English; you see it on all the old-time wayside hostelries over there.The Wrecker
Robert Louis Stevenson and Lloyd Osbourne
His copper-bottomed ships came up with and captured six of the enemy, five of which were English prizes.