MOSTLY civilians. A spokesperson for the IDF proudly declared a ratio of two civilians for every Hamas fighter and wouldn't show any data to back it up so it's almost certainly even worse than that!
https://en.wikipedia.org/wiki/Casualties_of_the_Israel%E2%80%93Hamas_war
The Gaza Health Ministry does not distinguish between combatant and civilian casualties in its reports. Hamas themselves have said they believe they have lost 6,000 fighters in the war, while the IDF claims up to 12,000 Hamas combatants were killed in Gaza as of 19 February 2024.
The current death toll is around 30,000 so between 1,5 and 4 civilians are killed for every Hamas fighter.
It's real.