Athwart \A*thwart"\, prep. [Pref. a- + thwart.]

1. Across; from side to side of.

Athwart the thicket lone. --Tennyson.

2. (Naut.) Across the direction or course of; as, a fleet standing athwart our course.

Athwart hawse, across the stem of another vessel, whether in contact or at a small distance.

Athwart ships, across the ship from side to side, or in that direction; -- opposed to fore and aft.

Source: Webster's Revised Unabridged Dictionary (1913)
 

Athwart \A*thwart"\, adv.

1. Across, especially in an oblique direction; sidewise; obliquely.

Sometimes athwart, sometimes he strook him straight. --Spenser.

2. Across the course; so as to thwart; perversely.

All athwart there came A post from Wales loaden with heavy news. --Shak.

Source: Webster's Revised Unabridged Dictionary (1913)