However, depending on the context, you could consider these options:
Based on the meaning of "power":
* Nishkriya (निष्क्रिय) - inactive, powerless
* Nirbal (निर्बल) - weak, feeble
* Ashakti (अशक्ति) - lack of power
* Balam (बलम) - powerless, helpless
Based on the meaning of "energy":
* Nishkriya (निष्क्रिय) - inactive, inert
* Nirjīv (निर्जीव) - lifeless, inanimate
Based on the meaning of "female divine energy":
* Shiva (शिवा) - the male divine energy
* Brahman (ब्रह्म) - the ultimate reality, beyond duality
Ultimately, the best opposite word will depend on the specific context in which "Shakti" is used.