mull over
To ponder or consider something. A noun or pronoun can be used between "mull" and "over." I need some time to mull over the options before I pick one.
mull something over
to think about something; to ponder or worry about something. That's an interesting idea, but I'll have to mull it over. I'll mull over your suggestions and reply to you next week.
mull over
Ponder, think about, as in She mulled over the offer for some time and then turned it down. [Late 1800s]