fucking

First recorded in 1520–30 for adjective sense, and 1860–65 as an intensifier; fuck + -ing²

Fucking and its euphemisms freaking, frigging, and fricking are used in adjectival or adverbial positions in a sentence as intensifiers. Something that is “fucking amazing” is really amazing. Someone who was there “the whole frigging time” was there for the absolute entirety of the time.
These words are also among a very small number of words that work as infixes in English. That is, they can also be placed inside of a word to act as an intensifier for that word, as in “absofuckinglutely” or “a-freakin-mazing.” When infixed, the informal variants (those with the final -g dropped from their spellings) are the more common forms. Infix-intensified words can be spelled with or without hyphens to set off the inserted word. While fucking and its euphemisms are the most common words used in this construction, “damned” is also sometimes infixed in American English, and in British English “bloody” and “blooming” can also be inserted in this manner.