adjective
1.
a. : tryingly or unremittingly severe in making demands or requiring the fulfillment of obligations
an exacting employer
b. : requiring careful attention and precise accuracy
an exacting task
2. : unable to thrive except under special conditions (as of nutrition, temperature, or moisture) : fastidious
an exacting microbe
certain highly specialized xerophytes are extremely exacting in their requirements
Synonyms: see onerous