पोटायुवतिस्तोककतिपयगृष्टिधेनुवशावेहत्बष्कयणीप्रवक्तृश्रोत्रियाध्यापकधूर्तैर्जातिः

A case-inflected word denoting a genus (जाति) is compounded with the words पोटा 'a hermaphrodite', युवति 'a young female', स्तोक 'a little', कतिपय 'a few', गृष्टि 'a cow which has had only one calf', धेनु 'milch cow', वशा 'a barren female', वेहद् 'a cow that miscarries', बष्कयणी 'a cow that has a full-grown calf', प्रवक्तृ 'an expounder', श्रोत्रिय 'a learned ब्राह्मण ', अध्यापक 'a teacher' and धूर्त 'a cunning fellow' and the resulting compound is तत्-पुरुष ।
As इभपोटा 'a young female elephant' इभयुवति 'a female elephant.' So also अग्निस्तोकः 'a little fire' उदश्वित् कतिपयम् 'a little butter milk,' गोगृष्टिः , गोधेनुः, गोवशाः , गोवेहत् , गोवष्कयणी, कठप्रवक्ता 'an expounder of Katha', कठश्रोत्रिय, 'a Bráhmana who has mastered the Katha branch of the Yajur Veda' कठाध्यापकः 'a teacher of the Katha branch of the Yajur Veda.'

Why do we say 'when denoting a genus or a common noun ?' Observe देवदत्तः प्रवक्ता 'Devadatta expounder.'

The word धूर्त has not a bad signification here. Hence कटधूर्त means 'a Brahmana well versed in the Katha branch of the Yajur Veda.'