Conversion is the word formation process whereby h a word of one grammatical form becomes a word of another grammatical form without any changes to spelling or pronunciation. Derivation is the word formation process whereby a derivational affix attaches to the base form of a word to create a new word.
In English, nouns can become verbs via conversion, and verbs can become adjectives via derivation. However, not all nouns can become adjectives with equal success.
“Warning: Boats are alarmed. No boarding without salesperson.”
Alarm (noun): A device that gives an audible, visual, or other form of alarm signal about a problem or condition
Alarm (verb): Cause (someone) to feel frightened, disturbed, or in danger
Alarmed (adjective): To feel frightened, disturbed, or in danger