reflect deeply on a subject; "I mulled over the events of the afternoon"; "philosophers have speculated on the question of God for thousands of years"; "The scientist must stop to observe and start to excogitate"
If you are ruminative, you are thinking very deeply and carefully about something. He was uncharacteristically depressed and ruminative. + ruminatively ru·mi·na·tive·ly He smiles and swirls the ice ruminatively around his almost empty glass. thinking deeply and carefully about something