Curved downward or inward.

(mathematics, of a claim) evident in the mind's eye, without formal proof being necessary.

overlapping; contorted; convoluted / (botany) Having two opposite leaves, each with one edge overlapping the nearest edge of the other.

In an obverse manner.

walled up

The act of turning toward or downward. / (logic) An immediate inference that denies the opposite of something previously affirmed.

plural of obversion

(obsolete) conversant; familiar

plural of obvention

(obsolete) The act of happening incidentally; that which happens casually; an incidental advantage; an occasional offering.