iTerm - going one word backwards and forwards
Killing a fly with a cannon:


Go to Preferences... > Profiles > Keys (not Preferences... > Keys)
Press Presets...
Select Natural Text Editing


Then, you can move a word backwards using Option ⌥ + ← and a word forwards using Option ⌥ + →, move to the start of the line using fn + ← and to the end of the line with fn + →. Also you can delete a word backwards using Option ⌥ + ⌫, delete the whole line using Command ⌘ + ⌫.

If the preset doesn't appear, reinstall iTerm2. If you installed it using Homebrew+Cask:

brew cask reinstall iterm2