1. (adjective) having no known beginning and presumably no end

• endless
• sempiternal

2. (adjective) not bearing a date

• undated

3. (adjective) unaffected by time

• timeless

1. (adjective) having no known beginning and presumably no end

• infinite

2. (adjective) of such great duration as to preclude the possibility of being assigned a date

• undatable

3. (adjective) not bearing a date

• undatable

4. (adjective) unaffected by time

• unaltered
• unchanged

1. (adjective) having no known beginning and presumably no end

• endlessness

2. (adjective) unaffected by time

• eternity
• timeless existence
• timelessness