A new blog that I installed using the TwentyFifteen theme has annoying hyphenation on the posts. I found an easy fix online. Open the style.css file and insert this at the end.
.entry-content,
.entry-summary,
.page-content,
.nav-links,
.comment-content,
.widget
{
-webkit-hyphens: none;
-moz-hyphens: none;
-ms-hyphens: none;
hyphens: none;
}