What does Judges 16:8 mean?

Delilah is lying to Samson: Philistines rulers are the real reason behind her questions (Judges 16:7). They have offered her a huge sum of money if she can use seduction to reveal the secret of Samson's strength (Judges 16:4–6). Samson, in turn, has lied to Delilah. He probably doesn't realize how untrustworthy she is. Yet he's playing along with what probably feels like a lover's game.

She has asked Samson what it would take to subdue him completely. He knows she is asking about his supernatural strength. Samson has told her, falsely, that being tied with seven fresh, undried bowstrings would make him as weak as any other man. That would make some sense, since Samson's Nazirite vow (Judges 13:4–5) prohibited contact with carcasses and corpses (Numbers 6:1–21). Bowstrings were made from dried animal intestine or other tendons. "Fresh bowstrings" were pieces of a dead animal.

Delilah's patrons provide the seven fresh bowstrings. She uses them to tie Samson up, perhaps as he sleeps. What she says next, Samson may have taken as a joke (Judges 16:9). It's not—Delilah has men waiting in case Samson is weak. Either way, he will easily snap the cords.