HN already supports title edits, so it's simpler than changing the CSS, and it's easier to read because the breaking is on the internal word boundaries. Here's the title with the zero-width spaces added:

CN Label Contact Relation Elder Cousin Mothers Siblings Daughter Or Fathers Sisters Daughter

EDIT: HN strips zero-width spaces and replaces them with normal spaces, so I can't post it here.

Then the title would not make sense anymore. Adding a simple css rule would also be futureproof, because i’m quite sure this is not going to be the last time an absurdly long title word appears.