Filial and Finial are easily confused words.
The spell-check application of most word processing software programs would not catch a slip-up of these two words. Spell-check is looking for words that aren’t in its dictionary, and words that resemble words in its dictionary but are possibly spelled wrong. Spell-check isn’t perfect. It doesn’t know and can’t guess what word you wanted or what word you meant, it can only judge the words on the page. If you used words that are all spelled correctly, it gives you a pass anyway.
Autocorrect suggests words that start with the same letters. It suggests what word you may want to save time, but quite often, its suggestions couldn’t be more off base and produces humorous results.
Filial is an adjective, it means relating to sons or daughters, or their relationship to their parents.
Finial is a noun. It means the decorative tips that are mounted at the edges of curtain rods and at the tops of posts on staircases. Finials are also found on typefaces’ elegant serifs.
The following story uses both words correctly:
Finola was a geneaologist, designer, and an accomplished fiddle player. She was delighted when some antique finials she found at a thrift store could be traced to their proper filial owners. Now those grown children could decorate their homes with items from their past.