perpetuo: continenter (☞ continue or continuo are not classical): sine intermissione: nullo temporis puncto intermisso (without ceasing): assidue (uninterruptedly; but assiduo is not classical): usque (always, without leaving off): semper (always, at all times). I am singing incessantly, ita cano, ut nihil intermittam: to work incessantly, nullum tempus ad laborem intermittere: to study incessantly, studia nunquam intermittere; totā vitā, assidere litteris; haerere in libris (to be always poring over one’s books): to entreat anybody incessantly, aliquem precibus fatigare.