1. endlessly, infinitely

continuing forever without end

Example Sentences:
'there are infinitely many possibilities'

• infinitely

2. ceaselessly, continuously, endlessly, incessantly, unceasingly, unendingly

with unflagging resolve

Example Sentences:
'dance inspires him ceaselessly to strive higher and higher toward the shining pinnacle of perfection that is the goal of every artiste'

• ceaselessly
• continuously
• incessantly
• unceasingly
• unendingly

3. endlessly

(spatial sense) without bounds

Example Sentences:
'the Nubian desert seemed to stretch out before them endlessly'

4. endlessly, interminably

all the time; seemingly without stopping

Example Sentences:
'a theological student with whom I argued interminably'
'her nagging went on endlessly'

• interminably