ر ب صr-b-ṣ
(ن) رَبَصَ يَرْبُصُ رَبْصًاrabaṣa yarbuṣu rabṣan: to lie in wait for an opportunity.
Form V (tafaʿʿul) تَرَبَّصَ يَتَرَبَّصُ تَرَبُّصًاtarabbaṣa yatarabbaṣu tarabbuṣan: to wait. ﴿وَالْمُطَلَّقٰتُ يَتَرَبَّصْنَ بِاَنْفُسِهِنَّ ثَلٰثَةَ قُرُوْٓءٍ﴾ (Al-Baqarah 2:228)
مُتَرَبِّصٌmutarabbiṣ (active participle, ism fāʿil): one who waits. ﴿قُلْ كُلٌّ مُّتَرَبِّصٌ فَتَرَبَّصُوْا﴾ (Ṭā Hā 20:135)