ˈstumbling ˌblock BrE AmE noun [countable]
a problem or difficulty that stops you from achieving something
stumbling block to
The main stumbling block to starting new research is that we lack qualified people.
ˈstumbling ˌblock BrE AmE noun [countable]
a problem or difficulty that stops you from achieving something
stumbling block to
The main stumbling block to starting new research is that we lack qualified people.
Longman Dictionary of Contemporary English. Longman - Словарь современного английского языка. 2012