Conversion is a Morphological process that is used to modify the grammatical class of words. To put it simply, it is used to change one part of speech into another one. It mostly involves the use of suffixes for Changing the syntactic category of a word. To elaborate, the word teach, sing and kill are verbs and when the "er" is added to these verbs, they become nouns.
1. Teach +er= Teacher. (v_N)
2. kill+er=Killer. (v_N)
3. Sing+we= Singer. (V_N)
Furthermore, the suffix "ly" when attached to adjectives turns them into adverb of manner.
1. Terrible +ly= Terribly (Adj_Adv)
2. Brave +ly= Bravely (Adj_Adv)
Similarly, the suffix "ness" creates abstract nouns from adjectives.
1. kind+Ness= kindness. (Adj_N)
2. Happy +ness= Happiness (Adj_N)
Thus, the afore-mentioned explanation shows the importance of conversion in forming new grammatical categories from the existing ones. In fact, the approach can be applied to crack the meaning of synonyms in various examinations such as the exam of Central superior services (CSS). There is a portion of synonyms and antonyms in the paper of English composition which can be handled well with this approach.