without > outside, beyond
5 Of this great garden, compassed with a mound,
compassed with > enclosed with; encircled by mound > embankment
6 Which overhanging, they themselves did steep 7 In a black flood which flowed about it round;
flood > river
8 That is the river of Cocytus deep,
Cocytus > (The "stream of wailing": one of the five rivers of hell: the others are Acheron, Phlegethon, Lethe, and Styx)
9 In which full many souls do endless wail and weep.
full > very, exceedingly
207.57