fall in with
verb1
To join (a group of people).
- He has fallen in with a bad lot.
- I went on alone and in the course of the days I fell in with many persons, stupid persons, great persons, jaunty ones.1922, A. E. Coppard, “Marching to Zion”, in Adam & Eve & Pinch Me:
2
To meet with (something).
- We had not sailed twelve hours before we fell in with a gale, which lasted several days, and we kept under close-reef-topsails and storm-staysails.1846, Frederick Marryat, “chapter 4”, in The Privateersman, or One Hundred Years Ago:
3
To accept, abide by (a set of generally agreed rules, or a suggestion).
- It seemed like a good idea, so we fell in with it.