This is the 4566th most frequent Russian word.
головные
"Головные" means "pertaining to the head" in English.
The word 'головные' here modifies 'уборы', meaning 'headwear', pertains to items worn on the head.
Он носит головные уборы даже дома.
He wears headwear even at home.
In this sentence, 'головные' refers to 'боли' (pains), specifically indicating those located in the head.
Головные боли не давали ему спокойно работать.
Headaches did not let him work peacefully.
Here, 'головные' qualifies 'мозги', denoting 'brains', particularly the ones within the heads of animals.