The act of learning new knowledge or material
When to use
Learning new subject, Starting exam preparation, Grasping basic concepts
The nuance
Use 공부하다 when learning new content or information for the first time.
공부하다 (gong-bu-ha-da, gongbuhada) · 복습하다 (bok-seup-ha-da, bokseuphada)
공부하다 means to learn new material, while 복습하다 means to review material already learned.

One lane per word — no nested boxes, just the gist.
The act of learning new knowledge or material
When to use
Learning new subject, Starting exam preparation, Grasping basic concepts
The nuance
Use 공부하다 when learning new content or information for the first time.
The act of studying material already learned again
When to use
Reviewing after class, Checking content before exam, Strengthening memory
The nuance
Use 복습하다 when reviewing or repeating material previously studied.
나는 매일 새로운 단어를 공부한다.
na-neun mae-il sae-ro-un dan-eo-reul gong-bu-han-da., na neun mae il sae ro un dan eo reul gong bu han da.
Learning new words fits 공부하다.
시험 전에 지난 수업 내용을 복습한다.
si-heom jeon-e ji-nan su-eop nae-yong-eul bok-seup-han-da., si heom jeon e ji nan su eop nae yong eul bok seup han da.
Reviewing previously learned material fits 복습하다.
어제 배운 문법을 공부했다.
eo-je bae-un mun-beop-eul gong-bu-haess-da., eo je bae un mun beop eul gong bu haess da.
Since the grammar was already learned, 복습하다 should be used instead of 공부하다.
새로운 수학 공식을 복습했다.
sae-ro-un su-hak gong-sik-eul bok-seup-haess-da., sae ro un su hak gong sik eul bok seup haess da.
New formulas should be studied (공부하다), not reviewed (복습하다).
영어 단어를 복습하는 것은 기억에 도움 된다.
yeong-eo dan-eo-reul bok-seup-ha-neun geos-eun gi-eok-e do-um doen-da., yeong eo dan eo reul bok seup ha neun geos eun gi eok e do um doen da.
Reviewing already learned words fits 복습하다.
처음 보는 역사 내용을 복습했다.
cheo-eum bo-neun yeok-sa nae-yong-eul bok-seup-haess-da., cheo eum bo neun yeok sa nae yong eul bok seup haess da.
New content should be studied (공부하다), not reviewed (복습하다).
수업 시간에 집중해서 공부했다.
su-eop si-gan-e jip-jung-hae-seo gong-bu-haess-da., su eop si gan e jip jung hae seo gong bu haess da.
Focusing in class learning new material fits 공부하다.
복습하지 않고 시험에 합격하기 어렵다.
bok-seup-ha-ji an-go si-heom-e hap-gyeok-ha-gi eo-ryeop-da., bok seup ha ji an go si heom e hap gyeok ha gi eo ryeop da.
Emphasizes the importance of reviewing before exams, fitting 복습하다.
Which word should you use when learning new words for the first time?
What is the act of reviewing learned material before exams?
What do you call learning new grammar?
What do you call memorizing words you've already learned again?
What does it mean?