conjecturally adv 1: in a manner involving or inclined to conjecture and supposition
Conjecturally \Con*jec`tur*al"ly\, n. That which depends upon guess; guesswork. [R.] --Sir T. Browne. [1913 Webster]
Conjecturally \Con*jec`tur*al*ly\, adv. In a conjectural manner; by way of conjecture. --Boyle. [1913 Webster]