Source: Tafsir al-Ahlam al-Kabir (Ibn Sirin)
The spider indicates a cursed woman who abandons her husband's bed. The spider's web is weakness and feebleness. Whoever sees a spider in his house will see a weak, frail man.
Source: Ta'tir al-Anam fi Ta'bir al-Manam (Al-Nabulsi)
The spider is a devout, ascetic man or a weaver. Killing it indicates expelling a corrupt man. Its house indicates weakness and lack of resourcefulness.
Source: Al-Isharat fi Ilm al-Ibarat (Ibn Shahin)
The spider is interpreted as a misguided man, woven into his sin. Whoever sees that he killed a spider will repent from a sin or move away from a bad friend.