Full text not returning any results

I'm having some issues with my full text indexes in MySQL 3.23.58. I'm
using I have a table with a full text index on the 'content' column.
There are some words that are returning results just fine but others
that should return results aren't.

For example,

SELECT * FROM lift_content WHERE match(content) AGAINST('content')
returns results just fine.

SELECT * FROM lift_content WHERE match(content) AGAINST('gangs')
doesn't return any results when there are rows that have the word
'gangs' in it.

Any thoughts on why certain words aren't returning results when they
should, and aren't included in the stopword list?

Thanks.