From Longman Dictionary of Contemporary English pounce on somebody/something phrasal verb 1 to criticize someone’s mistakes or ideas very quickly and eagerly Teachers are quick to pounce on students’ grammatical errors. 2 to eagerly take an opportunity as soon as it becomes available When they offered O'Leary the chance to become manager, he pounced on it. → pounce → See Verb table

pounce (up) on someone or something to spring or swoop upon someone or something; to seize someone or something. (Upon is formal and less commonly used than on.) As Gerald came into the room, his friend Daniel pounced on him and frightened him to death.

phrasal verb pounce on/upon something to quickly notice something that somebody has said or done, especially in order to criticize it synonym seize on/upon

pounce on something to quickly notice something that someone has said or done, especially in order to criticize it synonym seize on/upon something The press immediately pounced on his comments.