The words which are not derived or developed from other words are called primary words. Primary words are the original words in a language.
Some words are formed by joining two or more simple words. These words are called compound words. Examples are: sunlight, however, kindness, undertake etc.
These are words formed by making some changes to the spelling of a simple word.
Examples are given below:
Bond is a primary derivative formed by making some internal changes the word bind. Similarly, breach is a primary derivative formed by making some changes to the simple word break.
Note that past tense forms which are made by making some internal changes to primary verbs are not usually considered as derivatives.
These are formed by making an addition to the beginning or the end of a word. Examples are: unhappy and kindness.
Note that the addition made to the beginning of a word is called a prefix whereas an addition made to the end is called a suffix.
Most compound words are nouns, verbs or adjectives.
Compound nouns are usually formed by the following combinations.
Noun + noun
Examples are: railway, postman, shoemaker, horsepower, windmill, teaspoon, airman, manservant, screwdriver etc.
Armchair (arm + chair)
Sunlight (sun + light)
Adjective + noun
Examples are: shorthand, sweetheart, blackboard, stronghold, halfpenny etc.
Verb + noun
Examples are: spendthrift, makeshift, breakfast, daredevil, pickpocket, hangman etc.
Gerund + noun
Examples are: drawing room, bloating paper, stepping-stone, walking-stick, looking-glass etc.
Adverb/preposition + noun
Examples are: Outlaw, afterthought, foresight, bypass, downfall, afternoon
Verb + adverb
Examples are: drawback, send-off, die-hard, go-between etc.
Adverb + verb
Examples are: outset, upkeep, outcry, income, outcome etc.
Compound adjectives are formed from:
Noun + adjective
Examples are: blood-red, sky-blue, snow-white, skin-deep, pitch-dark, worldwide, lifelong, homesick, seasick etc.
Noun + participle
Examples are: heart-rending, ear-piercing, heartbroken, bedridden and lovelorn
Adjective + adjective
Examples are: red-hot, lukewarm etc.
Adverb + participle
Examples are: long-suffering, everlasting, outspoken, down-hearted, thorough-bred, inborn etc.
Compound verbs are formed from
Noun + verb
Examples are: earmark, browbeat, backbite, typewrite etc.
Adjective + verb
Examples are: safeguard, fulfill, whitewash etc.
Adverb + verb
Examples are: overtake, undertake, undergo, outbid, upset, outdo etc.