intentive
Paying attention; attentive, heedful.
the object is fine and accurate , it conduceth much to have the sense intentive and erect
Intent (of the mind, thoughts etc.).
To which whilest she lent her intentive mind, / He suddenly his net upon her threw […]
Expressing intent.
Where it comes from
From Middle English ententif, borrowed from Old French ententif, from Late Latin intentīvus (“intensive”), from Latin intendō (“to intend, to attend”).
Adapted from the Wiktionary entry intentive (CC BY-SA 4.0).