retortion
Concise Oxford English Dictionary © 2008 Oxford University Press:
retortion/rɪˈtɔːʃ(ə)n/
▶noun (in international law) retaliation by a state on another's subjects.
– origin C16 (in the sense ‘bending or turning backwards’): from retort1, perh. on the pattern of contortion.
'retortion' also found in these Oxford entries:

