1. 忽(hū)略(lüè)(neglect) is used when people neglect something unintentional, maybe because of the carelessness.
对(duì)不(bu)起(qǐ)，我(wǒ) 忽(hū)略(lüè)了(le) 这(zhè)个(ge) 细(xì)节(jié)。
Sorry, I neglected this detail.
2. 忽(hū)视(shì)(ignore) can not only functions as 忽(hū)略(lüè)(ignore), but is also used when ignoring someone intentionally because of the indifference and the contempt.
很(hěn)多(duō) 富(fù)人(rén) 忽(hū)视(shì)了(le) 穷(qióng)人(rén)的(de) 感(gǎn)受(shòu)
Many wealthy people ignored poor people’s feeling.
3. 疏(shū)忽(hū)(negligence) usually functions as noun.
因(yīn)为(wéi) 他(tā)的(de) 疏(shū)忽(hū)， 我(wǒ)们(men) 失(shī)败(bài)了(le)。
Because of his negligence, we failed.
As a Chinese learner, it would be better to remember these phrases:
(1) 不(bù)容(róng)忽(hū)视(shì)/ is not tolerant to ignore
(2) 忽(hū)视(shì)了(le)他(tā)的(de)感(gǎn)受(shòu)/ ignored his feeling
(3) 不(bù)能(néng)忽(hū)略(lüè)/忽(hū)视(shì)细(xì)节(jié)/ mustn’t ignore the details
(4) 由(yóu)于(yú)他(tā)的(de)疏(shū)忽(hū)/ because of his negligence
