Comparative evidence

ḱreth₂

• OInd. śrath-/ślath-/śranth- 'slacken' (Whitney 1885: 177); 'be loosened', 'be untied', 'be unbent', 'become loose', 'become slack', 'yield', 'give way'; 'make slack', 'disable', 'disarm'; 'loosen one's own' (bonds) (MW: 1096)

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.