noun
spunk
SPUNK/spʌŋk/
Lively courage and determination.
Even after several setbacks, she has the spunk to try again.

Etymology
The Gaelic ancestor names tinder as well as pith and sponge. English spunk meant a spark or tinder before developing the figurative sense of an inner spark of courage.
In context
I _am_ needed here. I am going to stay here.” “There’s spunk for you,” said Roaring Abel admiringly.
More examples
- It takes spunk to stand up to a bully.
- The coach admires the young team's spunk.
- Don't let one bad review crush your spunk.
Forms
spunky adjective — Showing lively courage and determination.