" ceaseless "

1: going on and on without any interruptions;

  * e.g., " ... there has been ceaseless rain for three days "

•  Synonyms : 

•  continual,

•  continued,

•  continuing,

•  continuous,

•  incessant,

•  nonstop,

•  perpetual,

•  running,

•  unbroken,

•  unceasing,

•  uninterrupted,

•  unremitting

•  Antonyms : 

•  discontinuous,

•  noncontinuous

2: lasting forever;

  * e.g., " ... promised her ceaseless happiness if she would only marry him "

•  Synonyms : 

•  dateless,

•  deathless,

•  endless,

•  eternal,

•  everlasting,

•  immortal,

•  permanent,

•  perpetual,

•  undying,

•  unending

•  Antonyms : 

•  impermanent,

•  mortal,

•  temporary,

•  transient