praeconstans

praeconstans [CL prae-+constans pr. ppl. of constare] , very steady, steadfast, or constant. b (superl., of person, as form of address). 1451 eas vestre ~anti amicicie cum immensis graciarum accionibus ‥ mittimus Pri. Cold. 174. b venerabilis frater et domine ~antissime Dictamen 346; ~antissime amice ‥ Ib. 369; c1413 reverende domine et avuncule ~antissime FormOx 425.