hortatory (adj.) Look up hortatory at Dictionary.com
1580s, from Middle French hortatoire and directly from Late Latin hortatorius "encouraging, cheering," from hortatus, past participle of hortari "exhort, encourage, urge, incite, instigate," intensive of horiri "urge, incite, encourage."

This is conjectured to be from the reconstructed PIE root *gher- (5) "to like, want" (source also of Old English giernan "to strive, desire, yearn;" Gothic gairnei "desire;" Greek khresthai "to lack, want; use, make use of," kharis "grace, favor," khairein "to rejoice, delight in;" Sanskrit haryati "finds pleasure, likes," harsate "is aroused;" Avestan zara "effort, aim;" Russian zhariti "awake desire, charm").

Older in English is hortation (1530s), from Latin hortationem.