英语的实词不但多义，而且同一词还可以属一种以上的词类。此外，从一种词类又可以转化为另一种词类，其中以⒈名词转化为动词、⒉动词转化为名词以及⒊形容词转化为动词，这三种最为普遍、最为生动。转化后的词具有该词基本的特性，因此转化名词有如真正名词，转化动词就像真正动词。
案例⒈名词→动词
① The workers found Bob's attitude hard to stomach.
② The parachutist had to nerve himself for the jump from his helicopter.
③ A few poor children had been dogging the tourists for some time.
④ Tuition schools have mushroomed for the last two years.
⑤ The traitor was knifed and stoned to death.
⑥ I leafed through a few pages of the book to see what it was about.
⑦ Personality clashes surfaced among some rival leaders.
⑧ Tom elbowed his way through the crowd.
⑨ It is impolite to ape one's superiors.
⑩ Delicious food made our mouths water.
⒉动词→名词
① The innocent girl was having a good cry.
② Active people are always on the go.
③ I often have a quiet read before going to bed.
④ People from all walks of life condemned a bad government.
⑤ Famine came in the wake of the drought.
⑥ The manager gave some lazy workers the sack.
⑦ Let me take a good look at these photos.
⑧ A visit to the Jurong Bird Park is a must for any tourist.
⑨ War is loathed by the haves and the have-nots.
⑩ If you have anything to discuss with me, don't hesitate to give me a ring.
⒊形容词→动词
① Don't idle away your precious time.
② Father's hair begins to grey.
③ How to quiet a fretful child?
④ We have no intention of seeing an innocent person humbled.
⑤ Something must be done to better the life of the underprivileged.
⑥ Language skills can be perfected by constant practice and regular reinforcement.
⑦ The robber wanted his victim to empty his pockets.
⑧ When the enemy's ships neared the land, our soldiers began to attack.
⑨ The man's muscles tensed as he saw the snake approaching him.
⑩ The hot weather soured the fresh milk.
此外，有些形容词和其他词类也可以转化为名词。例如：
① The strong tend to bully the weak.
② Poor innocents deserve our greatest sympathy.
③Richard looked like a silly in such a situation.
④ The secretary knows the ins and outs of the matter.
⑤ Do you know the whys and wherefores of the accident?
⑥ Though a rich man now, Peter's earlier life was marked by ups and downs.
上述这些转化名词，并未具有名词全部的特性。例如“the strong”和“the weak”形式是单数，意思是复数。还有④-⑥这些转化名词既有复数之形，也具复数之意。
