phreaking
Concise Oxford English Dictionary © 2008 Oxford University Press:
phreaking/ˈfriːkɪŋ/
▶noun informal, chiefly N. Amer. the action of hacking into telecommunications systems, especially to obtain free calls.
– derivatives
phreak noun,
phreaker noun.
phreak noun,
phreaker noun.
– origin 1970s: alt. of freaking by assoc. with phone.
'phreaking' also found in these Oxford entries:

