PER- (cf. παρά) = in a sense of wrong or injury.
perdere = destroy.
perfĭdus = faithless.
RED-, RE-, = back.
(i) = back, backwards.
rĕcumbere = lie down.
rĕflectere = bend back.
(ii) = in response, or return.
reddere = give in return.
(iii) = against, behind.
rĕpugnare = fight against.
rĕlinquere = leave behind.
(iv) = again.