野心満満
ya.shin.man.man

Literally: field – heart – full – full

Alternately: Bursting at the seams with (possibly secret) hopes and desires of grand scope. Burning with ambition.

Notes: This is a compound of compounds. 野心 on its own can be used for aspiration or ambition, especially ambition out of proportion to what the person is actually  capable of. In a more sinister vein, it can mean the kind of overweening ambition that leads to plots and treachery. 満満 (which may also be written with the doubling mark as 満々) is an emphatic doubling that simply means “full [of something].” A synonymous phrase replaces 満満 with 勃勃 (botsu botsu), “rising,” “energetic.”

One of my sources attributes this phrase to Chinese Qing-era drama The Palace of Eternal Life (Japanese 『長生殿』 = Chouseiden).

My dream is to one day have the biggest, poppedest collar in the whole world!