What happens when you add the suffix “ous” to the base word “poison”?

You have changed a noun into an adjective that describes poisons. Poison is also a verb (transitive, takes an object), but adding the suffix ‘-ous’ to a verb is ungrammatical (Or should that be ‘ungrammatic’? Spell check says no.)

It then becomes poisonous. Accuracy.

Glorious, Covetous, nervous, wondrous, continuous, fabulous, nacreous, precious.

Thanks

Not particularly.

Without taking help from Google, I could think of only few words ending -icular, like vehicular, perpendicular, curricular, etc., and they seem normal to me—neither good nor bad.

One of the very few rules of word formation in English is that the suffix -ous always forms an adjective.

After adding the suffix 'ous' the root word takes the form of an adjective. Example: poison+ous= poisonous.

“Defendant” is composed of “defend" + the suffix “-ant" which is used to denote someone in the act or process of carrying out the action contained in the stem.

“Defend" itself derives from Latin “de" (down or away) + “fendere" (strike).

Accordingly, “defendant" is composed of prefix (de) + root (fend) + suffix (ant).

“Fend" is used with “off" to mean to ward off or parry. With “for" it has the sense of getting by: to fend for oneself.

Adding “ous” to the noun word “poison” became “poisonous” which is turned to an adjective.

The “-ous” suffix creates adjectives that mean “full of,’ “laden with,” “containing,” “tending toward” or “characterized by…” whatever the base word is. A poisonous substance contains poison; a venomous snake carries venom; a glamorous film star is known for her glamor; a tedious lecture is characterized by tedium. A ferrous substance contains iron (because “ferrum” is the Latin word for iron).