Our Theresa's awful confinement (5,6)
I believe the answer is:
house arrest
'confinement' is the definition.
(house arrest is a kind of confinement)
'our theresa's awful' is the wordplay.
'awful' is an anagram indicator.
'our'+'theresas'='ourtheresas'
'ourtheresas' is an anagram of 'HOUSE-ARREST'.
(Other definitions for house arrest that I've seen before include "kept at home" , "detention" , "Domestic restriction" , "Confinement to one's own home" .)