Additional :D
The noun addiction has the adjective form additional and the adverb form additionally (in addition).The less-common related adjective and adverb are the derivatives additive and additively.
Cautious IS an adjective. An adjective is an action!
The word "it" is not an adjective (it is a pronoun). A word is an adjective if it modifies (defines, characterizes) a noun or pronoun. The big tent - big is an adjective He is tall - tall is an adjective This key - this (while arguably called a determiner) is a demonstrative adjective
probable is an adjective
Stable is an adjective.
additional
The noun addiction has the adjective form additional and the adverb form additionally (in addition).The less-common related adjective and adverb are the derivatives additive and additively.
The noun addition has the related adjective form additional and the adverb form additionally.
An adjective derivative (derivative adjective) is an adjective formed from a noun or verb by the addition of a suffix. Examples: glamor - glamorous honor - honorable plenty - plentiful
Adjective addition adding
The word 'additional' is the adjective form of the noun addition.
'Additional' is an adjective. It is used to describe or modify a noun in a sentence.
The phrase "in addition" is a prepositional phrase in which "in" is the preposition and "addition" is its object. This phrase, as a phrase, is not a part of speech, although it may function as one, probably an adjective or adverb.
"Just" can be an adjective or an adverb. It is not a noun.
"Joe do you have an extra pencil that I could borrow?"
No, the word 'just' can be used as an adjective and an adverb.
A derivative adverb would be the adverb form of a derivative adjective: one formed from a noun or a verb by the addition of a suffix (and possibly by a prefix as well). An example would be the adjective lawful (from the noun law) and the adverb lawfully.