noun
ADJECTIVE
▪ great , major , serious
▪ chief , main
▪ lawful ( BrE ), legal
▪
There are no legal ~s to their appealing against the decision.
VERB + IMPEDIMENT
▪ be , constitute , provide
▪ overcome
▪ remove
▪
The agreement is designed to remove ~s to trade between the two countries.
PREPOSITION
▪ ~ to
▪
Their boycott of the talks constitutes a serious ~ to peace negotiations.