Comparative evidence
kreph₁, kreph₂, kreph₃, kʷreph₁, kʷreph₂, kʷreph₃, kleph₁, kleph₂, kleph₃, kʷleph₁, kʷleph₂, kʷleph₃
• OInd. kṛp- 'lament' (Whitney 1885: 23); 'mourn', 'long for'; 'implore'; 'pity'; 'be weak' (MW: 305)
References
MW = Monier-Williams, M. 1899. A Sanskrit-English Dictionary. Clarendon Press.
Whitney 1885 = Whitney W. D. 1885. The roots, verb forms and primary derivatives of the Sanskrit language. A supplement to his Sanskrit grammar. Leipzig.