From Wikipedia: Never Weaken is a 1921 silent comedy film starring Harold Lloyd and directed by Fred Newmeyer. It was Lloyd's last short film, running to three reels, before he moved permanently into feature-length production. It was also one of his trademark "thrill" comedies, featuring him dangling from a tall building. Lloyd and his crew honed and perfected their "thrill" filming techniques in this film, and put them to astonishing use in the 1923 classic feature Safety Last!. Listed as Public Domain by Wikipedia.
You can stream Never Weaken (1921) free and legally on OldReel, via the Internet Archive.
Yes — it is in the public domain and can be watched and shared freely.