CONJECTURALLY
conjecturally
(adverb) in a manner involving or inclined to conjecture and supposition
Source: WordNet® 3.1
Etymology
Adverb
conjecturally (comparative more conjecturally, superlative most conjecturally)
In a conjectural manner.
Source: Wiktionary
Con*jec`tur*al"ly, n.
Definition: That which depends upon guess; guesswork. [R.] Sir T. Browne.
Con*jec`tur*al*ly, adv.
Definition: In a conjectural manner; by way of conjecture. Boyle.
CONJECTURAL
Con*jec"tur*al, a. Etym: [L. conjecturalis: cf. F. conjectural.]
Definition: Dependent on conjecture; fancied; imagined; guessed at;
undetermined; doubtful.
And mak'st conjectural fears to come into me. Shak.
A slight expense of conjectural analogy. Hugh Miller.
Who or what such editor may be, must remain conjectural. Carlyle.
Source: Webster’s Unabridged Dictionary 1913 Edition