прочный
firmus [a, um];
fortis [e] (pons fortis);
idoneus [a, um] (paries;
navis);
valens [ntis] (truncus);
validus [a, um] (abies);
fidus [a, um];
fidelis [e] (lorica;
navis;
societas cum aliquo);
stipulus [a, um];
stabilis [e] (regnum);
solidus [a, um];
perennis [e];
tenax [acis];
vivax [acis];
diuturnus [a, um];