Not every five-letter word is an equally good opener. Here's what actually separates a strong first guess from a weak one, so you can evaluate any word — not just memorize a list.
Your first guess can almost never be the correct answer by chance, so its job isn't to win — it's to gather the most useful information possible. Two things make a word better at that job:
A secondary factor is letter placement diversity — spreading vowels and consonants across different positions rather than clustering them, since that affects how much a yellow tile actually narrows things down.
None of these is objectively "the" best opener — they trade off differently. CRANE and SLATE balance vowels and consonants; ADIEU front-loads vowel information. Pick based on what you want to learn first.
The same logic applies with one more letter to work with. Words like GARDEN, PLANET, and MASTER spread common consonants (G/R/D/N, P/L/N/T, M/S/T/R) across six positions without repeating a letter. See 5-Letter vs 6-Letter Wordle for how the added length changes strategy more broadly.
Some players save their "best" word for later, assuming they should open with something safe. In practice, the opposite is usually better — front-load your most information-dense word first, since you have the most guesses left to act on what you learn. By your third or fourth guess, you should be narrowing candidates (ideally with the Wordle Helper) rather than testing fresh letters.
Because the hidden word is random, no single opening word is mathematically best in every case — some will occasionally get lucky and win in one guess, others won't. What you're optimizing for is the average amount of information gained, which is why letter frequency and distinctness matter more than any one memorized word.
Start a round and see how much a strong first guess narrows things down.