All 7 Uses of

tentative
in
A Prayer for Owen Meany

Students of the age of Dan's, and mine, have no great feeling—for example—for wit; wit simply passes them by, or else they take it to be an elderly form of snobbery, a mere showing off with the language that they use (at best) tentatively.†
p. 530.4 *

tentatively = in an unsure or hesitant manner

Hester stood still and put her hand out to Owen—her big paw, uncharacteristically tentative and gentle, reached out and touched his face, as if there were a force in Owen's immediate vicinity that compelled the passerby to touch him.†
p. 76.1

But although Owen agreed with me that the rector was a moron who messed up the Bible for tentative believers by assaulting us with the worst of God the Almighty and God the Terrible—and although Owen acknowledged that the Rev. Mr. Wiggin's sermons were about as entertaining and convincing as a pilot's voice in the intercom, explaining technical difficulties while the plane plummets toward the earth and the stewardesses are screaming—Owen actually preferred Wiggin to what little he knew of Pastor Merrill.†
p. 115.3

Grandmother regarded Owen uncertainly; before she allowed him to replace her at the open door, she reached outside and snatched her mail from Mr. Morrison's tentative hand.†
p. 198.8

Once, in Winston Churchill Park, when there were children roughhousing—at least, moving quickly—I saw someone about his size, standing slightly to the side of whatever activity was consuming the others, looking a trifle tentative but very alert, certainly eager to try what the others were doing, but restraining himself, or else picking the exactly perfect moment to take charge.†
p. 471.9

Definitions:

(1) (tentative as in: said it tentatively)
done in a careful or unsure way (indicating a lack of confidence in exactly what will happen)
(2) (tentative as in: a tentative plan)
subject to change (likely or possibly going to change)