answer back is a common REDUNDANCY, especially in BrE—e.g.: “Hilary and Piers du Pre seem determined to wreak the ultimate revenge on their sister by discrediting her while she lies—unable to answer back [read answer]—in her grave.” Julian Lloyd Webber, “An Insult to Jackie’s Memory,” Daily Telegraph, 4 Jan. 1999, at 15.
In AmE, the phrase is fairly common in sportswriting in the sense “to equal an opponent’s recent scoring effort”—e.g.:
• “Even when the Cougars did score, the Herd answered back in an instant.” Joe Davidson, “Herd Remain on a Roll,” Sacramento Bee, 21 Nov. 1998, at D1.
• “Jake Armstrong quickly answered back for the Knights, but the two-goal cushion was short-lived.” Joe Connor, “La Jolla, Bishop’s Tie One On in Wester,” San Diego Union-Trib., 16 Dec. 1998, at D6.
Some writers have used the sport phrase metaphorically—e.g.: “The last time somebody tried to impose prohibition on Chicago, the city answered back with Al Capone.” Peter Annin, “Prohibition Revisited?” Newsweek, 7 Dec. 1998, at 68. Despite the currency of this usage, answer can carry the entire load by itself.
LANGUAGE-CHANGE INDEX answer back for answer (outside sports): Stage 3
This pattern, where there is an exception to a rule when talking about a particular topic (or where a rule applies only when talking about the topic) will come up many times.
A similar thing could be used to detect what sport you're talking about to ensure that you don't talk about all of the hattricks that the other team scored after stealing a base and snookering a touchdown.
One of the entries in GMAU is:
This pattern, where there is an exception to a rule when talking about a particular topic (or where a rule applies only when talking about the topic) will come up many times.