Be necessary
Must and be necessary are semantically related. In some cases you can use "Must" instead a verb phrase "Be necessary".
Must
Must verb - To be under necessity or obligation to.
Mutual synonyms
Both terms in one sentence
- This is said to be necessary because of the way the prophecies were divided in the first place; great care must be taken to avoid another accident which, if it were to happen, could potentially unmake the universe.
Source: Prophecies Are Always Right -
In the novel Foundation's Triumph, the Three-Laws Compliant robots must use this type of phrasing when they tell human mentallics it may be necessary to seriously harm Hari Seldon to stop what they view as another robot group's interference.
Source: "Blackmail" is Such an Ugly Word -
When that doesn't work, she decides a "human sacrifice" must be necessary, so she attacks Shuri with a knife.
Source: Anime / Myself ; Yourself
Cite this Source
Must and Be necessary. (2016). Retrieved 2026, August 02, from https://thesaurus.plus/related/be_necessary/must
Be necessary & Must. N.p., 2016. Web. 02 Aug. 2026. <https://thesaurus.plus/related/be_necessary/must>.
Must or Be necessary. 2016. Accessed August 02, 2026. https://thesaurus.plus/related/be_necessary/must.
Google Ngram Viewer shows how "be necessary" and "must" have occurred on timeline