assumptive, assuming, forward, presumptious, overpresumptuous, præsumptuous, presuming, overweening, arrogative, arrogant, more...

modest, humble, unassuming

overly familiar,   over reaching,   rudely arrogant,   over familiar,   someone who assumes,   being forward,   quick to assume,   over assuming,   presume but rude,   bold to assume