Hi! Haven’t found your word but found some interesting ones whilst trying!
How about:
slantindicularly, adv.
In a slanting or sloping direction or position; obliquely.
Hattock. (dialect.)
A shock of standing sheaves of corn, the tops of which are protected by two sheaves laid along them with their bottoms in contact in the centre, and their heads slanting downwards, so as to carry off rain.
sklent, n. Sc. Also sclent.
[Sc. var. of slent n. Cf. the earlier asklent adv.]
A slant or slope; a slanting or sideward movement.

I particularly like slantindicularly – maybe difficult to drop into conversation though??

b.c.