頑張る【がんばる】
to persevere, to persist, to keep at it, to hang on, to hold out, to do one's best, to insist that, to stick to (one's opinion), to remain in a place, to stick to one's post, to refuse to budge
頑固【がんこ】
stubborn, obstinate, pigheaded
頑丈【がんじょう】
solid, firm, stout, burly, strong, sturdy
頑張って【がんばって】
do your best, go for it, hang in there, keep at it
頑強【がんきょう】
stubborn, dogged, persistent, tenacious, tough, sturdy, hardy, strong
頑張り【がんばり】
tenacity, endurance
頑な【かたくな】
obstinate, stubborn, mulish, die-hard, bigoted
頑として【がんとして】
stubbornly, firmly, determinedly, obstinately, resolutely, adamantly