Lower, Mark A (1860) Patronymica Britannica: a dictionary of the family names of the United Kingdom. London: J.R. Smith. Public Domain.
SUMPTION
As described in historical dictionaries
Patronymica Britannica (1860)
SUMPTION. This very remarkable name appears to be a contraction of " Assumption " (i.e., of the Virgin Mary), the church festival, and to be cognate with Pentecost, Chi-istmas, Easter, &c.