Exacting, a.
Oppressive or unreasonably severe in making demands or requiring the exact fulfillment of obligations; harsh; severe. "A temper so exacting." T. Arnold -- Ex*act"ing*ly, adv. -- Ex*act"ing*ness, n.
Shades of meaning
Fernald has no entry of its own for exacting; he lists it under absolute.
He lists it without comment; the entries above explain its neighbors.