tac-au-tac
Concise Oxford English Dictionary © 2008 Oxford University Press:
tac-au-tac /ˈtakəʊˌtak/
▶noun Fencing a parry combined with a riposte.
– origin early 20th cent.: Fr., lit. ‘clash for clash’, from imitative tac.
'tac-au-tac' also found in these Oxford entries:

