gumption - n. 1. bold, energetic initiative. 2. shrewd common sense. From English dialect (Scot.)
So initiative and shrewdness would be synonyms...
shrewd - adj. 1. sharp or wise; sagacious. 2. artful, sly. Middle English.
I think boldness would be a better synonym.
But I chose this word because
gumption is such a weird-sounding word. Most words that end with
tion are words on their own. For example, invention and action. But gump is not. Gump is a very harsh-sounding syllable, and is not in the dictionary.
It also does not have an adjective associated with it. May I suggest gumptuous? Rhymes with sumptuous. Now that is a horse of a different color. That one letter, which makes the initial sound,
G or
S, makes a BIG difference!