zeal·ous 
/ˈzɛləs/ adjective
/ˈzɛləs/ adjective [more zealous; most zealous] : feeling or showing strong and energetic support for a person, cause, etc. : filled with zeal
▪ zealous fans ▪ She was one of the president's most zealous [=ardent] supporters. ▪ The detective was zealous in her pursuit of the kidnappers.
▪ zealous fans ▪ She was one of the president's most zealous [=ardent] supporters. ▪ The detective was zealous in her pursuit of the kidnappers.
— zeal·ous·ly adverb
▪ She zealously pursued the kidnappers.
▪ She zealously pursued the kidnappers.
— zeal·ous·ness noun [noncount]
