I can't clearly see the differences between the meanings of 欠く, 欠ける, 欠かせる, and 欠かせない that I get from resources like Google Translate, Deepl, or wwwjdic. For example, if I enter the following in Deepl
彼は時間を欠く。
彼は時間が欠ける。
彼は時間を欠かせる。
彼は時間を欠かせない。
...the translation it produces is
He lacks time.
He lacks time.
He lacks time.
He lacks time.
This can't be right (for one thing, the fourth sentence is the direct negation of the third one, so their translations can't reasonably be identical).
If instead I give the same input to Google Translate, I get (sic)
he lacks time
he lacks time
he misses time
He needs time.
This is only marginally better: the translations for the third and fourth sentences are at least a little different, though much less so than I expected.
(In fairness to these tools, I must admit that some of the original sentences may be malformed, or at least weird. Please let me know if this is the case. In particular, I am insecure about the particles between 時間 and the verbs.)
Q: Can someone give me four sentences that clearly illustrate the differences among these four verbs?
Q: Regarding the last Japanese sentence in particular (彼は時間を欠かせない), how does it compare to the following two variantsvariant1?
彼は時間を欠かせなくいけない。
彼は時間を欠かせなければいけない。
FWIW, my best guess (and it is just a guess!) is that the literal translations four the original four sentences above are something like
He lacks time.
Time is lacked by him.
He makes/lets time lack.
He does not make/let time lack.
Granted, the first two translations have essentially the same general meaning, though differently worded. The last two literal translations sound particularly stilted. Slightly more idiomatic ones would be:
It is okay/possible for him to lack time. (= He does not require time.)
It is not okay/possible for him to lack time. (= He requires time.)
1The original version of my post included a second variant that I now think is downright ungrammatical, so I deleted it.