Comparative evidence

1.h₂er

• OInd. ṛ-/ṛch- 'go', 'send' (Whitney 1885: 14); 'move', 'rise', 'tend' (upwards); 'meet' (with), 'fall' (upon or into), 'reach', 'obtain'; 'occur', 'befall'; 'advance' (towards a foe), 'attack', 'invade'; 'hurt', 'offend'; 'excite', 'erect', 'raise' (MW: 223)

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.