FLAME-RETARDANT

flame-re·​tar·​dant | \ ˈflām-ri-ˌtär-dᵊnt

1. Too dumb to catch fire.

2. One whose thick skull is quantifiably too dense to allow enough oxygen within it conceptually, therefore rendering impossible the occurrence or actuation of combustion (metaphorically).

3. See also 'Dumb AF'*

*Dumb "As Fuck"