What makes a strong opening word
A good first guess does one job: it tests as many high-frequency letters as possible in one shot. The letters E, A, R, O, T, L, I, S, N and C appear far more often in five-letter answers than the rest of the alphabet, so a starting word built from that pool tells you the most about the day’s solution.
That is why words like CRANE, SLATE, TRACE, CRATE and SLANT consistently perform well — each uses five distinct, common letters with a sensible mix of vowels and consonants. ADIEU is popular because it packs in four vowels, but it wastes two consonant slots and often leaves you knowing the vowels without a clear next move.
There is no single “best” word, but there is a clear tier: pick something with five unique, common letters and at least two vowels, and avoid burning a guess on rare letters (J, Q, X, Z) or repeats on turn one.