- 孤独【こどく】 - solitude, loneliness, isolation 
- 独身【どくしん】 - bachelorhood, single, unmarried, celibate 
- 独立【どくりつ】 - independence, self-reliance, supporting oneself, being on one's own, independence (e.g. of a nation), freedom, separation, isolation 
- 独特【どくとく】 - peculiarity, uniqueness, characteristic, understood only by oneself 
- 独自【どくじ】 - original, unique, distinctive, characteristic, peculiar, independent, one's own, personal 
- 独占【どくせん】 - monopoly, monopolization, exclusivity, hogging, keeping to oneself 
- 単独【たんどく】 - sole, single, solo, independence, singleness, singularity 
- 独房【どくぼう】 - single cell, isolation cell, solitary cell, solitary confinement cell 
- 独裁【どくさい】 - dictatorship, despotism, autocracy, running (a company, etc.) despotically 
- 独断【どくだん】 - one's own judgement (judgment), decision made without consulting others, arbitrary decision, dogmatism 
- 独り占め【ひとりじめ】 - hogging, having all to oneself, monopolising, monopolizing 
- 独学【どくがく】 - self-education, self-instruction, self-study 
- 独り言【ひとりごと】 - soliloquy, monologue, speaking to oneself 
- 独立国【どくりつこく】 - independent state, independent nation 
- 独演【どくえん】 - solo, solo performance 
- 独奏【どくそう】 - (instrumental) solo, recital 
- 独禁法【どっきんほう】 - antitrust law, Antitrust Act 
- 独唱【どくしょう】 - vocal solo 
- 西独【せいどく】 - West Germany (1949-1990) 
- 独走【どくそう】 - running alone, running solo, having a large lead (over the others), being far ahead (of everyone else), having one's own way, ignoring others' opinions and acting as one wishes, arbitrary action