ambitious
Concise Oxford English Dictionary © 2008 Oxford University Press:
ambitious/amˈbɪʃəs/
▶adjective having or showing ambition.
■ (of a plan or piece of work) intended to satisfy high aspirations and therefore difficult to achieve.
– derivatives
ambitiously adverb,
ambitiousness noun.
ambitiously adverb,
ambitiousness noun.
'ambitious' also found in these Oxford entries:

