soft brick

When a phone's system is unusable or not bootable at all, but you can access the recovery or download mode, you can call it a soft brick/it gets soft-bricked. After downloading the original software, it should return to the usable state. It often happens after flashing a custom system.
A hard brick is similar, yet the very opposite. - A hard brick is a literal brick, because the firmware is well fucked up and you cannot even access the download mode.

"flashing" -> Copying/downloading a (custom) system onto an Android phone
"ROM" -> system
"Fastboot/Download mode" -> a mode on an Android phone that allows you to flash files directly into a phone's filesystem

I have a soft bricked phone. I was just going to flash the stock software on it.