• aux. 必須，一定；可以，應當；很可能
• n. 絕對必要的事物；未發酵葡萄汁
• n. (Must)人名；(匈)穆什特；(俄、瑞典)穆斯特

來自古英語motan,有能力做，有必要做，-st,過去分詞后綴，來自Proto-Germanic*mot,能力，力量，來自PIE*med,測量，衡量，采取手段，詞源同measure,medical.其在古英語時期語氣并不是很強烈，后不斷強化。比較noblesse oblige.

來自拉丁語vinum mustum,新酒，新釀葡萄酒，來自mustus,新鮮的，水靈的，來自PIE*meus,濕的，帶水氣的，詞源同mist,moist.

must

must: English has three words must. By far the commonest is of course the verb, ‘have to’ [OE], which originated in Old English as the past tense of the now obsolete mūt ‘may, must’. It has relatives in German muss and Dutch moet, but its ultimate origins are not known for certain (there may be some distant link with Germanic ‘measure’-words, such as English mete, suggesting a semantic progression from an original ‘time measured out for doing something’, through ‘have time to do something’, ‘be able to do something’, and ‘be allowed to do something’ to ‘have to do something’). Must ‘unfermented grape juice for making into wine’ [OE] comes from Latin mustum ‘new wine’, a noun use of the adjective mustus ‘new’. Mustard is a derivative.

And the esoteric must ‘sexual frenzy in elephants, camels, etc’ [19] comes via Urdu from Persian mast ‘drunk’.
=> mustard

must (v.)

Old English moste, past tense of motan "have to, be able to," from Proto-Germanic *mot- "ability, leisure (to do something)" (cognates: Old Saxon motan "to be obliged to, have to," Old Frisian mota, Middle Low German moten, Dutch moeten, German müssen "to be obliged to," Gothic gamotan "to have room to, to be able to"), perhaps from PIE root *med- "to measure, to take appropriate measures" (see medical (adj.)). Used as present tense from c. 1300, from the custom of using past subjunctive as a moderate or polite form of the present.

must (n.1)

"new wine," Old English must, from Latin mustum (also source of Old High German, German most, Old French moust, Modern French mo?t, Spanish, Italian mosto), short for vinum mustum "fresh wine," neuter of mustus "fresh, new, newborn," perhaps literally "wet," and from PIE *mus-to-, from root *meus- "damp" (see moss).

must (n.2)

"mold," c. 1600, perhaps a back-formation of musty (q.v.).

must (n.3)

"male elephant frenzy," 1871, from Urdu mast "intoxicated, in rut," from Persian mast, literally "intoxicated," related to Sanskrit matta- "drunk, intoxicated," past participle of madati "boils, bubbles, gets drunk," from PIE root *mad- "wet, moist" (see mast (n.2)).

must (n.4)

"that which has to be done, seen, or experienced," 1892, from must (v.). As an adjective, "obligatory, indispensable," by 1912, from the noun; must-read is from 1959.

1. You must have noticed how tired he sometimes looks.

你一定注意到他有時候顯得特別疲憊。

來自柯林斯例句

2. "His memory must be completely back, then?" — "Just about."

“這么說，他的記憶一定是完全恢復了？”——“差不多。”

來自柯林斯例句

3. There must be any number of people in my position.

一定有很多人處在我這種境況。

來自柯林斯例句

4. I must have driven past that place thousands of times.

我得有上千次開車經過那里。

來自柯林斯例句

5. "You must come to Tinsley's graduation party." — "I'd be delighted."

“你一定要來參加廷斯利的畢業聚會?！薄拔液軜芬?。”

來自柯林斯例句