"And it came to pass afterward, that he loved a woman in the valley of Sorek, whose name was Delilah" (Judges 16:4). Rabbi Meir used to say: even had her name not been called Delilah, she would have deserved to be called Delilah, for she impoverished [dildelah] his strength, she impoverished his heart, she impoverished his deeds. She impoverished his strength, as it is written, "and his strength went from him" (Judges 16:19). She impoverished his heart, as it is said, "And when Delilah saw that he had told her all his heart" (Judges 16:18). She impoverished his deeds, as it is written, "and he knew not that the LORD was departed from him" (Judges 16:20).
Why Delilah Was Rightly Named for Impoverishing Samson
Yalkut Shimoni on Nach 70:7
ויהי אחרי כן ויאהב אשה בנחל שורק ושמה דלילה, היה ר' מאיר אומר אלמלי לא נקרא שמה דלילה היתה ראויה שתקרא דלילה שדלדלה את כחו דלדלה את לבו דלדלה את מעשיו, דלדלה את כחו דכתיב ויסר כחו מעליוו, דלדלה את לבו שנאמר ותרא דלילה כי הגיד לה את כל לבו. דלדלה את מעשיו דכתיב והוא לא ידע כי ה' סר מעליו: