Definition of keep up

• maintain a required pace or level; "He could not keep up and dropped out of the race"
• prevent from going to bed at night; "The anticipation of the trip kept the children up all night"; "I kept myself up all night studying for the exam"
• lengthen or extend in duration or space; "We sustained the diplomatic negotiations as long as possible"; "prolong the treatment of the patient"; "keep up the good work"