to understand something; to start behaving reasonably. Sometimes said in angry response to a person's undesirable behaviour: 'cop (yourself ) on' IRELAND, 1991
cop on
1. noun Common sense or basic logic. Sometimes hyphenated. Primarily heard in Ireland. It seems like no one in government has any cop on these days.
2. verb To wise up; to employ common sense or logic; to understand the situation. Primarily heard in Ireland. You really need to cop on to what's expected of you as an adult.We all copped on that we had overstayed our welcome.