Then he frowned and displayed busr (a premature, intense scowl).

"Then he frowned"—he knit his brow when he could find no fault in it [the Quran], when stratagems became constricted for him, and he did not know what to say. It is said: He then looked at the faces of the people, then knit his brow. It is also said: He looked at the Messenger of Allah (may Allah, exalted be He, grant him peace and blessings) and knit his brow at his face (upon him be peace and blessings).

And he displayed busr—meaning he exhibited the frown before its proper time and out of its season. Al-busr is the hastening of a thing, such as saying, "The man basara a need," meaning he sought it before its proper time; or, "The stallion basara the she-camel," meaning he covered her before she was ready; or, "One basara that which is drawn from a pool before it has settled." It is said of cheese that is consumed before it has matured that it is busr, and from this, unripe fruit is called busr. It is in this sense that al-Raghib interpreted it here.

Others interpreted it as the most severe form of frowning, derived from basara when one constricts the area between the eyes due to loathing for a thing, and his face darkens because of it. It is also used with the same meaning as "frowning," as in the saying of Tawbah: It has troubled me, her turning away that I witnessed, / And her aversion to my need, and her busur (scowling).

And in the saying of Sa’d: "When I accepted Islam, my mother opposed me; she would meet me at one time with bishr (cheerfulness) and at another with busr (scowling)." Thus, the mention of busr acts as an emphasis for ’abasa (frowned). Perhaps this is what is intended by those who say it is a derivative follow-up. The people of the right say basara and absara when he pauses. I have not seen the permissibility of intending that meaning here, even remotely; and regarding the confirmation of that being linguistically sound, the soul remains in hesitation.