deficient in quantity or number compared with the demand
"fresh vegetables were scarce during the drought"
Uncommon, rare; difficult to find; insufficient to meet a demand.
"Fresh water is scarce in this desert region, making it hard for travelers to stay hydrated during their journey."
In plain English: Scarce means there is not enough of something to meet everyone's needs, so it is hard to find.
"Fresh water is scarce in this part of the desert during summer."
almost not
"he hardly ever goes fishing"
"he was scarce sixteen years old"
"they scarcely ever used the emergency generator"
"I can hardly hear what she is saying"
"she barely seemed to notice him"
"we were so far back in the theater, we could barely read the subtitles"
Scarcely, only just.
"He arrived so late that he was scarcely in time to catch the last train."
The word scarce comes from Middle English and Old Northern French terms that originally meant "sparing" or "miserly." Although some scholars suggest it may have evolved from a Late Latin phrase meaning "taken out," its exact origin remains uncertain because the shift in meaning is difficult to trace.