名詞 counterfeit:

1. a copy that is represented as the original
   同義詞：imitation, forgery

動詞 counterfeit:

1. make a copy of with the intent to deceive
   同義詞：forge, fake

形容詞 counterfeit:

1. not genuine; imitating something superior
   同義詞：imitative

1. Money, especially counterfeit money.
   偽鈔錢，尤其指偽造的錢幣
2. This note is counterfeit, but that one's good.
   這張鈔票是假的，那張是真的。
3. She counterfeited alarm when he confessed his love.
   當他向她示愛時她假裝驚訝的樣子。
4. Counterfeit or fake.
   假冒的，偽造的

coun.ter.feit

v.（動詞）
coun.ter.feit.ed,coun.ter.feit.ing,coun.ter.feits
v.tr.（及物動詞）
To make a copy of, usually with the intent to defraud; forge:
贗造，偽造：復制，通常目的為了詐騙；偽制：
例句：
counterfeits money.
偽造錢幣

To make a pretense of; feign:
假裝；偽裝：
例句：
counterfeited interest in the story.See Synonyms at pretend
對這個故事假裝感興趣參見 pretend

v.intr.（不及物動詞）
To carry on a deception; dissemble.
進行欺騙；佯裝
To make fraudulent copies of something valuable.
仿造，假冒：制造一些有價值東西的贗品
adj.（形容詞）
Made in imitation of what is genuine with the intent to defraud:
偽造的，仿造的：為了詐騙而模仿真的東西而做的：
例句：
a counterfeit dollar bill.
偽制美元鈔票

Simulated; feigned:
冒充的；假裝的：
例句：
a counterfeit illness.
裝病

n.（名詞）
A fraudulent imitation or facsimile.
摹本：詐騙性的模仿或摹真本

來源：
Middle English countrefeten
中古英語 countrefeten
from contrefet [made in imitation]
源自 contrefet [模仿做的]
from Old French contrefait [past participle of] contrefaire [to counterfeit]
源自 古法語 contrefait [] contrefaire的過去分詞 [仿制]
contre- [counter-]
contre- [反逆，代替]
faire [to make] from Latin facere * see dhô-
faire [做] 源自 拉丁語 facere *參見 dhô-

【引伸】
coun.terfeit.er
n.（名詞）