You can use it with a noun to modify it or to add to it.
Happy is already an adjective.
Yes, you can use the adjective dramatic.
The adjective form for the verb to use is the past participle, used (a used car).The adjective form for the noun use is useful(useful information).
Yes, It Almost Has The Meaning As The Adjective.
Yes, the term 'untidy clothes' is a correct use of the adjective.
a good adjective is ugly
the adjective is captive - the noun is captivity
Yes you can use it as an adjective by saying someone is 'arachnophobic'
An adjective describes a noun.
"Obsolete" is an adjective. It describes something that is no longer in use or outdated.
never
Use the suffix -ly when you want to change an adjective to an adverb. Ex: The girl is beautiful; adjective The girl spun around beautifully; adverb