You searched for: “-acious
-aceous, -acious, -atious

This confusing ending is pronounced the same in all three spellings.

-aceous (AY shuhs) A suffix that becomes an (adjective)
Characterized by, relating to a group; such as, a plant family. Of the common words, only curvaceous ends in -aceous; however, a great many technical terms from botany, zoology, chemistry, medicine, etc. have this spelling: herbaceous, sebaceous, setaceous, etc.:

The biology class went on a hike to collect the leaves from several herbaceous plants in the park.

-acious (AY shuhs) A suffix that becomes an (adjective)
Full of, characterized by, or tending toward. The most frequent form in use is -acious: audacious, gracious, pugnacious, etc.:

Billy's teachers observed that he was a pugnacious boy when he was with other children on the playground.

-atious (AY shuhs) A suffix that becomes an (adjective)
Inclined to "-ation" or, some say that the suffix is actually "-ous" and means "full of". The following end in -atious: disputatious, flirtatious, ostentatious, vexatious. Note that for each of these there is a corresponding noun in "-ation": disputation, flirtation, ostentation, and vexation.:

Carol's friend, Isabel, is very flirtatious or playful with boys.

Keep in mind that "-acious" is more than likely to be the correct ending whenever there is any serious doubt as to which suffix to use.

If Ivan is very cautious, he will be gracious to the botanist who is studying the herbaceous growth patterns on the local hillside.

A unit related to: “-acious
(Latin: suffix; forming adjectives; inclined to, given to, tendency to be, abounding in)