What does it mean and how can I fix it?
zsh compinit: insecure directories, run compaudit for list.
Ignore insecure directories and continue [y] or abort compini
I got this issue after running the google-cloud-sdk install script, which adds command-completion to the shell via an entry in .zshrc.
Following Homebrew's instructions for configuring completions in zsh was helpful.
Additionally, if you receive “zsh compinit: insecure directories” warnings when attempting to load these completions, you may need to run this:
chmod -R go-w "$(brew --prefix)/share"