Synonyms for Ideate:

n.

ideate (noun)
imagine, conceive of, envisage.

v.

imagine (verb)
opine, create, fantasize, envision, imagine, invent, consider, design, observe, think, reflect, contemplate, plan, brainstorm, theorize, perceive, conceive, suppose.
think (verb)
consider, reflect, conceive, imagine.

Other synonyms:

Other relevant words:
envisage, conceive of.