```python
import string

def slug_word(word: str) -> str:
    """Lowercase a word and drop non-letter/digit characters."""
    return ''.join(char for char in word if char.isalnum())

def slug_make(phrase: str) -> str:
    """Join slugged words of a phrase with single hyphens, ignoring empty words."""
    slugs = [slug_word(word) for word in phrase.split()]
    return '-'.join(slug for slug in slugs if slug)
```