Must-have

n.capable, joyfuleveryday

What it means

Something regarded as especially necessary, useful, or desirable to possess.

Reach for it when making an informal high-priority recommendation while leaving room for context

A refillable water bottle is a must-have for this exposed summer route.

playful
nonnegotiable
when a boundary or need admits no compromise
not when The term is forceful and can shut down reasonable alternatives.
playful
top pick
when strong preference, not necessity, is the honest claim
not when Top pick is promotional and does not establish practical need.
everyday
necessity
when people cannot reasonably proceed without the item
not when Necessity can ignore alternatives and differences in circumstance.
everyday
staple
when an item is routinely useful or foundational
not when A staple is common and recurring, not necessarily required for one task.
professional
essential
when something is genuinely necessary for safety or function
not when Essential is stronger and belongs only where need, not preference, is real.
professional
prerequisite
when something must exist before a later step can begin
not when Prerequisite concerns sequence and eligibility, not general desirability.
professional
priority
when something should be obtained or addressed before lower-value options
not when A priority can be important without being an object to possess.
professional
requirement
when a rule or specification makes something mandatory
not when Requirement invokes an authority and misfits a personal recommendation.
formal
indispensable
when no adequate substitute is available
not when Indispensable is an absolute and often promotional overstatement.

absolute must-have
A working headlamp is an absolute must-have for the night survey.
considered a must-have
The guide is considered a must-have by many local birders.
travel must-have
A paper copy of the address is a useful travel must-have.

Must-have is informal recommendation language and often marketing hype. Use essential only where the need is real and context-specific.

The definition and the example on this page are written here. The dictionaries above ground which meaning is being described, not the wording.