ثاقب بالانجليزي

very sensitive and well developed (of the senses)

لَدَىْ الصُّقُوْرِ نَظَرٌ ثَاقِبٌ

Hawks have acute sight

used to describe the fact of a person looking very carefully at someone or something, especially when they are trying to discover something, often making people feel uncomfortable (of eyes, looks, etc)

نَظَرَ إِلَيَّ بِعَيْنَيْنِ ثَاقِبَتَيْنِ

He looked at me with piercing eyes

نَظَرَتْ إِلَيْهِ نَظْرَةً ثَاقِبَةً

She gave him a piercing gaze