The word 费劲 is formed through the combination of two characters: 费 (fèi), meaning "to spend" or "to consume", and 劲 (jìn), meaning "strength" or "effort". Together, they create a compound word whose literal meaning is "to spend effort". This morphological process is typical in Mandarin, where two meaningful morphemes are combined to produce a new, specific concept, in this case, an adjective describing something that requires a lot of physical or mental exertion, or feels arduous and troublesome. The term thus moves from a literal description of expending energy to a common figurative expression for anything that is difficult or a hassle.