頑張れ

The 命令形 (meireikei, “command or imperative form”) of verb 頑張る (ganbaru, “to do one's best, to work hard, to persist”).

The kanji spelling is an example of ateji (当て字)

• (Tokyo) がんば​れ [gàńbáꜜrè] (Nakadaka – [3])
• IPA^(key): [ɡã̠mba̠ɾe̞]

頑(がん)張(ば)れ • (ganbare) 

1. (imperative, exhortation) do your best, good luck, hang in there, come on, don't give up, keep going

Used for encouragement or cheering on (where English "good luck" is often used), its actual meaning is closer to "do your best" or "give it your best". As a phrase, it does not contain any reference to luck, but rather effort and hard work. Compare French bon courage.

As the strong imperative form, it may be considered rude if used directly to a single person. Consequently, this term is more often used when cheering on a team or group. To encourage a single person, the conjunctive (weaker imperative) form 頑張って (ganbatte) is more common.