rough go (adjective) formidable: difficult, overwhelming
Sinonime: all-powerful,
arduous,
awesome, ballbuster, challenging,
colossal, dismaying, effortful,
great,
hard,
impressive,
indomitable,
intimidating, labored,
laborious, mammoth,
mighty,
murder*,
onerous, overpowering,
powerful, puissant, rough go,
rough*,
staggering,
strenuous, tall order, toilsome, tough proposition,
tough*,
tremendous, uphill
Antonime: easy, not hard,
pleasant,
trivial