When Judah saw her, he thought she was a harlot, because she had covered her face.
Genesis 38:15
Surrounding context
38:14 So she took off her widow's garments, covered herself with a veil and wrapped herself, and sat in an open place which was on the way to Timnah; for she saw that Shelah was grown, and she was not given to him as a wife.
38:15 When Judah saw her, he thought she was a harlot, because she had covered her face.
38:16 Then he turned to her by the way, and said, "Please let me come in to you"; for he did not know that she was his daughter-in-law. So she said, "What will you give me, that you may come in to me?"