fortassis
form analysis and translation based on Perseus (Version 2010):
GEN S N
fortassis ADJ  perhaps, probably, possibly, it may be that
Helmut Schmid's TreeTagger with Latin data by Gabriele Brandolini: fortassis ADV
Georges, Ausführliches lateinisch-deutsches Handwörterbuch, 8. Aufl. (1913)
fortāssis, Adv. (aus forte an si vis), vielleicht, Plaut., Sen. rhet. u.a.
Lewis & Short, A latin dictionary (1879)
fortassis, fortassis, adv., v. fortasse init.
Gaffiot, Dictionnaire latin-français (2016, ex 1934), merci à G. Gréco, M. De Wilde, B. Maréchal, K. Ôkubo!
fortassis fortassis, adv., peut-être : Cic. Sest. 121 ; Clu. 144 ; 201 ; Pl. Bacch. 671 ; Hor. S. 1, 4, 131 ; 2, 7, 40 ; Plin. 2, 82 ; 27, 102.
Дворецкий И.Х., Отличный латинско-русский словарь (1976)
fortassis fortassis adv. [из forte an si vis] Pl, C, H, Sen etc. = forsitan.