nolle prosequi
Concise Oxford English Dictionary © 2008 Oxford University Press:
nolle prosequi /ˌnɒlɪ ˈprɒsɪkwʌɪ/
▶noun Law a formal notice of abandonment by a plaintiff or prosecutor of all or part of a suit.
– origin L., lit. ‘refuse to pursue’.
'nolle prosequi' also found in these Oxford entries:

