exacting in WordNet English dictionary

1. having complicated nutritional requirements; especially growing only in special artificial cultures
   "fastidious microorganisms"; "certain highly specialized xerophytes are extremely exacting in their requirements"
   fastidious  exacting 
   
2. requiring precise accuracy
   "an exacting job"; "became more exigent over his pronunciation"
   exigent  exacting 
   
3. severe and unremitting in making demands
   "an exacting instructor"; "a stern disciplinarian"; "strict standards"
   stern  strict  exacting