Is this your crossword clue?
"surely" is also used as a crossword clue. If that's what you saw, the answer is often undoubtedly (11 letters).
Definitions
definitely or positively (‘sure’ is sometimes used informally for ‘surely’)
Word origin
From Middle English surely; equivalent to sure + -ly.
Used in a sentence
“slowly but surely”
“Surely, you must be joking.”
“You don’t suppose we're going to pay for you, surely?”
Source: Wiktionary, CC BY-SA 4.0
Used as a crossword answer1 curated clues
01“Certainly”6 letters
Not quite right?
"Search similar patterns."
S_____