informal if you are in someone's good books, they are pleased with you.
I cleaned the bathroom yesterday so I'm in Mum's good books.
(redirected from be in good books)
be in (someone's) bad books
To have fallen out of favor with someone due to having offended or mistreated them. I don't think I'll come to the party on Saturday because I'm in Jenny's bad books at the moment.
get into (someone's) bad books
To fall out of favor with someone due to offending or mistreating them. I must have gotten into Jenny's bad books because I wasn't invited to her party on Saturday.
be in/get into somebody’s ˈgood/ˈbad books
(informal) have/not have somebody’s favour or approval: I’m in his bad books at the moment because I accidentally broke the window.‘Why are you cleaning her shoes?’ ‘I’m trying to get into her good books!’