Energetic person dashed our hopes about our team (10)
I believe the answer is:
powerhouse
'energetic person' is the definition.
('powerhouse' can be a synonym of 'energetic person')
'dashed our hopes about our team' is the wordplay.
'dashed' is an anagram indicator.
'about' indicates putting letters inside.
'our team' becomes 'we'.
'our'+'hopes'='ourhopes'
'ourhopes' with letters rearranged gives 'porhouse'.
'porhouse' placed around 'we' is 'POWERHOUSE'.
(Other definitions for powerhouse that I've seen before include "Remarkably forceful person" , "Dynamic person" , "Dynamo" , "Energetic person" , "Person with great energy" .)