1
general::
Free time spent in much the same pursuit as one's work. For example, Weather permitting, the lifeguard spent all her days off at the beach? a real busman's holiday. The term alludes to a bus driver spending his day off taking a long bus ride. [Late 1800s]
American Heritage Idioms
2
general::
Phrase(s): a busman’s holiday
leisure time spent doing something similar to what one does at work. (Alludes to a bus driver going on a bus tour for his vacation or on a day off.) • Tutoring students in the evening is a busman’s holiday for our English teacher. • It’s a bit of a busman’s holiday to ask her to be wardrobe mistress for our amateur production in the summer. She’s a professional dressmaker.
McGrawhill's American Idioms And Phrasal Verbs