flash the pan (noun) flash in the pan: momentary success
Sinonime: clandestine,
concealed,
confidential, covert,
creep, furtive, hidden, hole-and-corner, hush-hush,
incognito*,
intelligence, on the QT, private,
stealth, stealthy, sub-rosa,
surreptitious, under wraps,
underground, underhand, underneath
Antonime: known, open,
public