tidying up after an event; clearing up; settlement
Refers to the act of putting things away, cleaning up, or settling affairs after something is finished, such as after a party, work, or a task. Often implies a final wrap-up.
Thank you for helping with the cleanup after the party.
I'll go home once I finish tidying up after work.
後片付け is a more common synonym for post-event cleanup, but 後仕舞 carries a nuance of final settlement or winding up.
Compound of 後 (あと, 'after') and 仕舞 (しまい, 'end' or 'finish'), literally meaning 'after-finish' or 'winding up afterwards'.