Literally: (this one’s complicated…)
This is the Navajo word for ‘lightning’ (also sometimes written as ‘atsinil-tlish). It’s also the word used for ‘electricity.’
The ‘tłish’ part is most likely referring to a sound, such as a loud clap (or, you can imagine a metal pot falling onto the hard floor).
It’s hard to say exactly what the ‘atsinil’ part references. (If you happen to know, I’d love your feedback!)
If it’s storming where you are, look out for lightning!