hypothecate

verbs

pledge without delivery or title of possession
hypothecate
is a type of (narrower)
give as a guarantee
"I pledge my honor"
pledge
to believe especially on uncertain or tentative grounds
"Scientists supposed that large dinosaurs lived in swamps"
conjecture, hypothecate, hypothesise, hypothesize, speculate, suppose, theorise, theorize
is derived from
hypothesis
is derived from
hypothesis