1. a task completed with excellence; superior work
do/did a bang-up job
'A bang-up job' is a 'good job' or something which has been completed to a high standard. This phrase is usually used as a compliment given to someone following a job well done. This is more of a colloquial expression to use with people you know rather than in formal situations. Similar phrases include 'a great job' and 'a top notch job'.