Synset

(of e.g. speech and writing) tending to depart from the main point or cover a wide range of subjects
<adj.all>

digressive

discursive

excursive

rambling

sample sentences

"amusingly digressive with satirical thrusts at women's fashions among other things"
"a rambling discursive book"
"his excursive remarks"
"a rambling speech about this and that"