Definitions:

1. In a way that never stops, especially when this is annoying or unpleasant. ADVERB
   • The clock ticked incessantly, marking the slow passage of time in the quiet room.
2. Without interruption or relief, continually, or in an unceasing manner. ADVERB
   • She talked incessantly during the movie, making it hard for anyone else to follow the plot.
3. Without interruption; constantly. ADVERB
   • Rain fell incessantly for days, causing the rivers to swell and flood the surrounding areas.

Synonyms:

• ceaselessly
• constantly
• continuously
• endlessly
• unceasingly
• unendingly