-itious1
/ˈɪʃəs/suffix
Forming adjectives corresponding to nouns ending in -ition (such as ambitious corresponding to ambition).
Origin
From Latin -itiosus.
-itious2
/ˈɪʃəs/suffix
(Forming adjectives) related to; having the nature of: fictitious suppositious
Origin
From late Latin -itius, alteration of Latin -icius.