形容詞 regardless:

1. (usually followed by `of') without due thought or consideration
   同義詞：careless

副詞 regardless:

1. in spite of everything; without regard to drawbacks
   同義詞：irrespective, disregardless, no matter, disregarding

1. She is determined to do regardless of all consequences.
   她不顧一切后果，決心這樣做。
2. I protested, but she carried on regardless.
   我極力反對，但她置之不理仍一意孤行。
3. They decorated the house regardless of cost.
   他們不惜工本裝修這棟房子。
4. All our proposals were rejected, regardless of their merits.
   我們所有的建議都遭到拒絕，不管這些建議的價值如何。

re.gard.less

adv.（副詞）
In spite of everything; anyway:
不顧后果；無論如何：
例句：
continues to work regardless.
不顧后果地繼續(xù)工作

adj.（形容詞）
Heedless; unmindful.
毫不在意的；毫不顧及的

【引伸】
regard.lessly
adv.（副詞）
regard.lessness
n.（名詞）