形容詞 reckless:

1. marked by defiant disregard for danger or consequences
   同義詞：foolhardy, heady, rash
2. characterized by careless unconcern
   同義詞：heedless

1. Courage, especially when reckless.
   蠻勇勇氣，尤指不顧后果的勇氣
2. He's a reckless driver.
   他是個(gè)魯莽的司機(jī)。
3. He's quite reckless of his own safety.
   他完全不顧及自己的安全。
4. His brother is a reckless gambler.
   他的弟弟是個(gè)不計(jì)后果的賭徒。

reck.less

adj.（形容詞）

Heedless or careless.
粗心的：不注意的或粗心大意的
Headstrong; rash.
魯莽的：草率的；莽撞的
Indifferent to or disregardful of consequences:
不顧后果的：對(duì)后果不關(guān)心或忽視的：
例句：
a reckless driver.
橫沖直撞的司機(jī)

來源：
Middle English reckeles
中古英語 reckeles
from Old English rôcelôas * see reg-
源自 古英語 rôcelôas *參見 reg-

【引伸】
reck.lessly
adv.（副詞）
reck.lessness
n.（名詞）
<參考詞匯><同義詞>reckless,rash,precipitate,foolhardy,temerariousThese adjectives are compared as they mean given to or marked by unthinking boldness.
當(dāng)這些形容詞都表不加思考的魯莽的意思時(shí)，常把它們進(jìn)行比較。
Reckless suggests brazen indifference to or defiant disregard for consequences:
Reckless 指對(duì)后果厚顏無恥的冷漠或輕蔑的忽視：
例句：
.James . . . became the fiercest and most reckless of partisans. (Macaulay).
.詹姆士…變成了一個(gè)最魯莽且不顧后果的黨徒. （麥考利）。

Rash implies haste, impetuousness, and insufficient consideration:
Rash 暗指匆忙、沖動(dòng)且沒有足夠考慮的：
例句：
.Take calculated risks. That is quite different from being rash. (George S. Patton).
.精細(xì)估算后再去冒這個(gè)險(xiǎn)。這與魯莽大大不同. （喬治·S·巴頓）。

Precipitate connotes headlong haste without due deliberation:
Precipitate 暗示沒有審慎考慮的輕率匆忙：
例句：
.destroyed in a precipitate burning of his papers a few days before his death. (James Boswell).
.在臨死前的幾天中他匆忙地?zé)龤Я宋募? （詹姆士·鮑斯韋爾）。

Foolhardy implies injudicious or imprudent boldness:
Foolhardy 暗指不明智的或不謹(jǐn)慎的莽撞：
例句：
One of the hostages was foolhardy enough to try to wrest the gun from the hijacker`s hand.
有一個(gè)人質(zhì)莽撞地企圖去奪劫機(jī)者手中的槍。

Temerarious suggests reckless presumption:
Temerarious 指不顧后果的傲慢：
例句：
.the temerarious use of Christian names. (H.G. Wells).
.傲慢地使用教名. (H·G·威爾斯）