名詞 formal:

1. a lavish dance requiring formal attire
   同義詞：ball
2. a gown for evening wear
   同義詞：dinner dress, dinner gown, evening gown

形容詞 formal:

1. being in accord with established forms and conventions and requirements (as e.g. of formal dress)
2. characteristic of or befitting a person in authority
3. (of spoken and written language) adhering to traditional standards of correctness and without casual, contracted, and colloquial forms
4. represented in simplified or symbolic form
   同義詞：conventional, schematic
5. logically deductive
6. refined or imposing in manner or appearance; befitting a royal court
   同義詞：courtly, stately

1. We were invited to a formal luncheon.
   我們被邀參加一次正式的午宴。
2. At the formal party I felt very awkward and out of place.
   在正式的舞會(huì)上，我感到局促不安，很不自在。
3. He is very formal with everyone; he never joins in a laugh.
   他對(duì)任何人都很拘謹(jǐn)，從不跟人說笑。
4. There is only a formal likeness between the two brothers, for their natures are very different.
   這兩兄弟僅外表相似，本性卻很不一樣。
5. Business letters must always be formal, but we should write in a natural way to friends.
   商業(yè)信函必須是正式的，但是寫信給朋友應(yīng)寫得自然一些。

for.mal

adj.（形容詞）

Relating to or involving outward form or structure.
外形的，形式的：關(guān)于或涉及事物外在形式或結(jié)構(gòu)的
Being or relating to essential form or constitution:
形式的：屬于事物的基本形式或構(gòu)成的：
例句：
a formal principle.
形式原則

Following or being in accord with accepted forms, conventions, or regulations:
正規(guī)的：遵循或符合規(guī)定的形式、慣例或規(guī)則的：
例句：
had little formal education; went to a formal party.
受過很少的正規(guī)教育；參加一個(gè)正規(guī)聚會(huì)

Executed, carried out, or done in proper or regular form:
正式的：以適當(dāng)或常規(guī)形式進(jìn)行的：
例句：
a formal reprimand; a formal document.
正式譴責(zé)；正式文件

Characterized by strict or meticulous observation of forms; methodical:
正式的，符合傳統(tǒng)或習(xí)慣的：在形式上嚴(yán)格拘泥于細(xì)節(jié)的；有條理的：
例句：
very formal in their business transactions.
他們的商務(wù)議事很有條理

Stiffly ceremonious:
刻板的：
例句：
a formal manner; a formal greeting; a formal bow to the monarch.
刻板的儀態(tài)；刻板的歡迎；向君主刻板地鞠躬

Having the outward appearance but lacking in substance:
形式的，表面的，徒有其表的：只有表面現(xiàn)象而沒有實(shí)體的：
例句：
a formal requirement that is usually ignored.
通常被忽略的表面條件

n.（名詞）
Something, such as a gown or social affair, that is formal in nature.
禮服：性質(zhì)上屬于正式的東西，如長(zhǎng)禮服和社交活動(dòng)

來源：
Middle English
中古英語
from Latin fôrm3lis
源自 拉丁語 fôrm3lis
from fôrma [shape]
源自 fôrma [形狀]

【引伸】
for.mally
adv.（副詞）
for.malness
n.（名詞）