The affixes kru and klukana come in the sense of 'agent having such a habit etc.' after the verb bhī 'to fear'.,
As, भीरुः 'fearful, timid'; भीलुकः 'timorous, a bear, a tiger, a jackal'.
Vart:- The affix क्रुकन् should also be stated; as भीरुकः ।,
भियः क्रु-क्लुकनौ
Adhyāya 3 · Pāda 2 · Rule 174