Q: deleting videos imported from your mac, OFF your iphone

Hi there mmdvm,

Welcome to Apple Support Communities.

It sounds like you want to know how to delete videos from your iPhone 6. Take a look at the article below which outlines the process for deleting entire seasons of TV shows or individual videos. 

Delete music, movies, apps, and other content from your iPhone, iPad, or iPod touch - Apple Support

Delete movies, TV shows and music videos

Remove movies, TV shows, and other videos from the Videos app.

Remove movies, entire TV show seasons, or music videos

Tap Edit, then tap   in the upper-left corner of the season, music video, or movie that you want to delete. When you're done, tap Done.

Remove individual TV show episodes

Find the episode that you want to delete. Swipe left on the episode, and tap Delete.

Also, you can choose the content that's synced to your iPhone as shown in this article:

Sync your iPhone, iPad, or iPod touch with iTunes using USB - Apple Support

Cheers.

Thank you for using Apple Support Communities. Due to the nature of the issue, you may find more information by using another one of these Apple support resources - https://getsupport.apple.com/GetproductgroupList.action.