FLUID

Meaning

Any substance which can flow with relative ease, tends to assume the shape of its container, and obeys Bernoulli's principle; a liquid, gas or plasma.

• adjectiveOf or relating to fluid.

FLUID as a word-puzzle answer

FLUID is a 5-letter word with 2 vowels (U, I) and 3 consonants (F, L, D). Every letter is distinct, so it rarely punishes a clean opening guess.

It leans on high-frequency letters (I), so a strong vowel-and-common-consonant opener tends to light up quickly. There are no rare letters here, so it is a fair, mid-difficulty answer for the daily Classic puzzle.