Abhinivesha is a concept that appears in the Yoga Sutra. It is one of the five kleshas.
The verse that explains it is svarasavAhI viduSho 'pi tathArUDhah abhiniveshah. This is translated as "Even for the wise the flow of guNas is firmly established."
Now it is very important to realize that the Yoga Sutra is an experiential text. Many mere scholars or dry commentators cannot explain this concept because it is something that has to be experienced.
The proper experience of abhinivesha happens just before samAdhi. After the kuNDalinI shakti is awakened and led up the cakras to the sahasrAra, the final frontier is the bindu. Intense meditation is required at this stage to penetrate the bindu. This is called bindu vedhana. The mind has to become so unburdened of past impressions, thoughts and baggage, and so one-pointed that it can pass through this portal which is smaller than a mustard seed.
Beyond bindu lies the ultimate freedom. The mind freed from its bondage to the body can merge into that Bliss which is pure Consciousness. But at the time of leaving the body a great fear can arise. This fear is that of losing the physical body forever and not being able to return to the earthly plane and to enjoy those earthly pleasures through the senses. This clinging is abhinivesha. Beyond the bindu is the guNAtIta state. But the flow of guNas is firmly established even for the wise.
The wisdom by which one is able to give up this clinging comes only by the grace of God. Then refocusing the mind on the PraNava the aspirant bravely gives up the last attachment and soars up to merge with the Infinite.
The experience of samAdhi is simply an early simulation of the experience of death. At the time of death the mind is involuntarily made to leave the body. In samAdhi the yogi voluntarily leaves the body through effort of meditation, which is nothing but aligning himself with the Cosmic Power. Thus the yogi who has attained samAdhi does not fear death any more.
After the experience of samAdhi, depending on the strength of past karma, the yogi returns to the body to play out the remaining vAsanas.
Later it is realized that it is a form of abhinivesha that results in our reappearance in the same physical body after each night's sleep.
Finally, it is seen that this extends to each succession of thought. Indeed, it is abhinivesha that enables the continuity of human experience as a jIva by allowing the mind to connect one thought to another as the caterpillar climbs from one leaf to the next. Without this continuity of clinging, individuated human experience is not possible. And yet, from a yogi's perspective, this clinging prevents the continuous direct experience of the Seer resting in one's own nature, which is sahaja samAdhi. Nevertheless, even a glimpse of the Truth that leads to strong conviction of the infallibility of the path, eventually leads to the effortless state.