An adjective is a word that is used to describe the qualities of a Noun or Pronoun.
Some examples of Adjectives - 
Person Related - affectionate, brave, clever, efficient, fair, gentle, honest, innocent, jealous, kind, etc.
Place Related - broad, narrow, crowded, waterlogged, slippery, etc.
House Related - airy, big, spacious, remote, stuffy, untidy, vacant, etc.
Things Related - fresh, rotten, sour, dirty, thin, murky, etc.