the.com/high road

means The ethically better course of action — staying dignified, fair, or honest — especially when taking the low, petty, or dishonest path was right there on offer.

from Literally the main, well-maintained public road as opposed to muddy back lanes and shortcuts — 'high' meaning principal or chief, as in 'high street.' By the 1700s the phrase had widened into metaphor: the 'high road' was the open, respectable way of doing something, and 'low road' its disreputable shadow. The moralized contrast got cemented in popular use (the old song 'The Bonnie Banks o' Loch Lomond,' with its 'high road' and 'low road,' helped fix the phrase in everyday speech), and from there it settled into its modern job — the dignified path you take when you can't win, or won't stoop.