Thanks Slaney - that was my preference but I was not terribly happy with scilicet particularly as sp is abbreviation for sine prole which translates as without issue. Are you still sure?
Hi maxymax, I'm not doing this crossword, but namely means much the same as "that is to say", and I would be happy with silicet (sc).
Sine prole - without issue or offspring (childless) does not fit at all.