Synonyms for Assuming:

adj.

all (adjective)
assumptive, presumptuous.
believing (adjective)
Hoping.
brave (adjective)
bold.
presumptuous, arrogant (adjective)
egotistic, bold, forward, pushy.
trusting (adjective)
believing.

n.

conjunction, correlative, causal, Albeit, coordinating conjunction, although, And, Andor. sassy, fresh, audacious, Familiar, smart, impertinent, saucy, pert, Snippety, overconfident, cheeky, contumelious, pushy, brash, attitude, brazen, bold, smart-alecky, Malapert, impudent, uppity, flip, boldfaced, courtesy, nervy, wise, brassy, snippy, insolent, uppish. arrogant (noun)
bold, egotistic.
assuming (noun)
presumptuous, forward, assumptive.

v.

acquiring (verb)
Receiving, Palming, harvesting, Retrieving, Garnering, netting, taking, purchasing, getting, Luring, Amassing, Adding, Annexing, scoring, buying, fetching, Securing, Claiming, Accumulating, Procuring, Obtaining, winning, incurring, acquiring, catching, Cornering, landing, bagging, Pocketing, collecting, wrangling, Capturing, Heaping, Reaping.
believing (verb)
Deeming, concluding, assenting, Crediting, professing, believing, accepting, Affirming, taking for granted, Presuming, Supposing, understanding, holding, putting faith in, trusting, Surmising, giving faith, gathering, judging, Declaring, Maintaining.
expecting (verb)
Presupposing, Deducing, Suspecting, Awaiting, Inferring, Anticipating, Apprehending, foreseeing, foreboding, Expecting, Contemplating, Foreknowing, Envisaging, Imagining, Dreading, envisioning.
hoping (verb)
yearning, Intending, wishing, Relying, Desiring, dreaming of, aspiring, Hoping, wanting.

Other synonyms:

Snippety, correlative, sassy, Albeit, causal, contumelious, cheeky, coordinating conjunction, And, smart-alecky, boldfaced, although, pushy. nervy, impertinent, uppish, brassy, Malapert, overconfident, saucy, conjunction, impudent, snippy, uppity, egotistic. pert, brazen, brash. bold, audacious, insolent, smart. Familiar. fresh. wise. Other relevant words:
Familiar, And, brazen, pushy, impertinent, insolent, uppity, brash, correlative, fresh, audacious, pert, impudent, flip, assumptive, egotistic, Snippety, wise, presumptuous, overconfident, saucy, Malapert, sassy, smart, causal, snippy, cheeky, bold, brassy, nervy, uppish, Albeit, boldfaced, forward, smart-alecky, contumelious.

Usage examples for assuming

  1. This in itself is not difficult, but you should try to discover in how many different ways the puzzle may be solved, assuming that in every case the two rows at starting are exactly the same. – Amusements in Mathematics by Henry Ernest Dudeney
  2. Assuming then, for the sake of argument, that these historical premises are sound, I proceed to consider how they bear on our prospective civilization. – The Emancipation of Massachusetts by Brooks Adams