Clue: Grounds to invest in South America (8)
Answer: SUSPENDS
Explanation: Definition: Grounds
 SPEND(to invest/to employ, say, time or effort, doing something for a cause) **contained in**(in) [ S(abbrev. for "south") + US(abbrev. for the United States of America) ].
Defn: Prevents an activity from happening, such as the social activities of child who is being punished.