It can also mean to endure or suffer, to decide in favour of something, substantiate, corroborate or maintain.
One who sustains is a sustainer. Do you qualify for that description?
Sustaining interest in our writing can be something which makes many writers feel insecure. For some it can seem like they're enduring the writing process rather than being supported and encouraged by it.
For others, the worry is how to sustain a reader's interest, either as they're reading one piece, or in their writing as a whole.
If any of those, or anything else is making you feel like an insecure writer, then you might like to consider joining the Insecure Writer's Support Group.
For me, the issue making me feel most insecure at the moment is how to achieve a sustainment of sales for my lovely books. I probably need to do some form of marketing, perhaps even make a sustained effort in that direction?
This free to enter short story competition has the theme of sustainability. The first prize is £200 – if you don't want it, feel free to send it over and I'll recycle it for you!