Third-person singular simple present indicative form of keep up.
I'm going to be an expert if this keeps up.
The construction of the tombs commonly keeps up the same analogy between the cities of the living and those of the dead.
Sanitation decreases the death-rate, religion keeps up the birth-rate.
Legend tells stories of his teaching men picture-writing and the calendar, and also the artistic work of the silversmith, for which Cholula was long famed; but at last he departed, some say towards the unknown land of Tlapallan, but others to Coatzacoalcos on the Atlantic coast on the confines of Central America, where native tradition still keeps up the divine names of Gucumatz among the Quiches and Cukulcan among the Mayas, these names have the same meaning as Quetzalcoati.
Philostratus keeps up the mystery of his hero's life by saying, "Concerning the manner of his death, if did die, the accounts are various."