A value that cannot be estimated is one that is incommensurable, incalculable, or lacks sufficient, reliable data to be quantified. Examples include intangible, subjective, or infinite concepts such as the true value of human life, the exact number of grains of sand, or the emotional "value" of a personal memory.
unpredictable. When something's unpredictable, it doesn't happen at expected times or it can't be predicted. If trains were unpredictable, they wouldn't follow a set schedule and you'd never know when one would arrive. The adjective unpredictable can also describe something that's unexpected or not known in advance.
immeasurable. Something immeasurable can't be measured or quantified.
Definitions of unforeseen. adjective. not anticipated. “unforeseen circumstances” synonyms: out of the blue, unanticipated, unlooked-for.
Use the adjective worthless to describe something that has no use or isn't worth any money. Your old broken-down car, a stamp collection with no value, and your no-good roommate who never cleans and won't pay his share of the rent could all be described as worthless.
Everything from vintage cookware to old-school gaming consoles can be worth more than you might imagine.
There's no single "rarest word" as rarity depends on context (obscurity vs. usage), but words like " acnestis" (the spot between shoulder blades an animal can't reach) or "nudiustertian" (the day before yesterday) are incredibly rare, while words like "sesquipedalian" (long-winded) or "syzygy" (alignment of celestial bodies) are uncommon but known by some. Many rare words describe specific, seldom-needed concepts, making them obscure but useful when needed, like "accismus" (feigning disinterest) or "librocubicularist" (someone who reads in bed).
inestimable. in•es•ti•ma•ble /ɪnˈɛstəməbəl/ adj. that cannot be estimated; incalculable:inestimable harm.
Synonyms for TBD (To Be Determined) include undetermined, pending, undecided, to be decided, to be defined, to be discussed, or forthcoming, all indicating something is not yet finalized, decided, or known and requires future action or information.
Definitions of incalculable. adjective. not capable of being computed or enumerated. countless, infinite, innumerable, innumerous, multitudinous, myriad, numberless, uncounted, unnumberable, unnumbered, unnumerable.
: too great, valuable, or excellent to be measured. He has made inestimable contributions to our society. inestimable value/worth.
unannounced, unheralded, unpredicted. without warning or announcement. out of the blue, unanticipated, unforeseen, unlooked-for. not anticipated. unhoped, unhoped-for, unthought, unthought-of.
adjective. impossible to achieve. “an unattainable goal” synonyms: unachievable, undoable, unrealizable. impossible.
pauciloquent (comparative more pauciloquent, superlative most pauciloquent) Using few words when speaking.
(uncountable) The practice of using long, sometimes obscure, words in speech or writing.
Synonyms
7 English words that nobody uses anymore (but totally should)