How many letters does the top answer for “enduring strength and energy” have?

The most common answer is stamina (7 letters).

Crossword clue: enduring strength and energy

2 answers found in Letterora's clue database (Wikidata facts, Open Trivia DB, WordNet and Webster definitions — all licensed sources).

stamina 7 letters wn-def

enduring strength and energy

toughness 9 letters wn-def

enduring strength and energy

depleted of strength or energy 50% similar → tired