頑張る

Etymology
Derivation uncertain. The two leading theories are:


 * Sense shift from
 * Shift in pronunciation from

The sense was originally to be stubborn, to be obstinate, with negative overtones. The modern positive sense of to persist, to endure has arisen since the end of the in 1868.

The spelling is, using the  character to express a sense of. The historical kana reading comes from the use of this  character, and is not related to either of the expected derivations above.

Some sources use both and  as spellings for the persist, endure sense. Other sources split these out as entirely separate entries.

Verb

 * 1) to work hard and do one's best to achieve a goal
 * 2) to strive unrelentingly in the face of difficulty, to persevere
 * 1) to strive unrelentingly in the face of difficulty, to persevere