adjective
1.
Synonyms: lasting , diuturnal, durable, perdurable, perduring, permanent, stable
Antonyms: fleeting
2.
Synonyms: old 2, continuing, inveterate, lifelong, long-lasting, long-lived, perennial
3.
Synonyms: sure 2, abiding, firm, never-failing, steadfast, steady, unfaltering, unqualified, unquestioning, wholehearted
Related Word: durable, resolute, solid, sound, stable, staunch, sturdy, substantial
Contrasted words: capricious, changeable, fickle, inconstant, mercurial, unstable, variable