Class, category, genus, species, denomination, genre are compared here only in their general, nonspecialized use, and the following comments may be inapplicable to such technical fields as philosophy and the sciences.
Category: Synonyms
Claim vs Title vs Pretension vs Pretense
Claim, title, pretension, pretense are comparable when they denote an actual or alleged right to demand something as one's possession, quality, power, or prerogative.
Civilization vs Culture
Civilization, culture are comparable when meaning the particular state or stage of advancement in which a race, a people, a nation, a specific class, or an integrated group of these finds itself at a given period.
Civil vs Polite vs Courteous vs Courtly vs Gallant vs Chivalrous
Civil, polite, courteous, courtly, gallant, chivalrous are comparable as applied to persons or their words and acts when in intercourse with others with the meaning observant of the forms required by good breeding.
Civic vs Civil vs Civilian
Civic, civil, civilian are not close synonyms but rather words whose meanings lend themselves to confusion.
Citizen vs Subject vs National
Citizen, subject, national are comparable when denoting a person who is regarded as a member of a sovereign state, entitled to its protection, and subject to its laws.
Circumstantial vs Minute vs Particular vs Particularized vs Detailed vs Itemized
Circumstantial, minute, particular, particularized, detailed, itemized are comparable when they mean dealing with a matter point by point.
Circumference vs Perimeter vs Periphery vs Circuit vs Compass
Circumference, perimeter, periphery, circuit, compass are comparable because all in their basic senses denote a continuous line enclosing an area or space.
Choose vs Select vs Elect vs Opt vs Pick vs Cull vs Prefer vs Single
Choose, select, elect, opt, pick, cull, prefer, single are comparable when they mean to fix upon one of a number of things as the one to be taken, accepted, or adopted or to make such a determination.
Choice vs Exquisite vs Elegant vs RecherchÉ vs Rare vs Dainty vs Delicate
Choice, exquisite, elegant, recherché, rare, dainty, delicate are comparable when they mean having qualities that appeal to a fine or highly refined taste.
Choice vs Option vs Alternative vs Preference vs Selection vs Election
Choice, option, alternative, preference, selection, election are comparable when they mean the act or opportunity of choosing or the thing chosen.
Chirp vs Chirrup vs Cheep vs Peep vs Tweet vs Twitter vs Chitter
Chirp, chirrup, cheep, peep, tweet, twitter, chitter can all mean as verbs to make the little sounds characteristic of small animals and as nouns the little sounds so made, and all can be extended to sounds and the making of sounds (as by human beings) that suggest such small animal sounds.