Section 138 of Indian Succession Act, 1925 applies to case where the testator has devised an absolute estate to the legatee, but ha specifically added a clause, which has the effect of reducing his power to deal with that property as an absolute estate.
In such case, the restriction placed on the right of the legatee needs to be rejected on account of its being repugnant to the absolute bequest. It provides for divestment of the estate which has already vested but is subject to be divested by some act or event at a future date. The defeasance must be in favour of somebody in existence at the time when the bequest is made.
Example: A testator gave his property to his two daughters as ‘owners’ but provided that on their death daughters shall be the heirs. Held that the daughters took estate absolutely.