As adjectives the difference between saggiest and snaggiest
is that saggiest is superlative of saggy while snaggiest is superlative of snaggy.
saggiest
English
Adjective
(head)
(saggy)
saggy
English
Adjective
(er)
Baggy or loose-fitting.
That sinks or droops from wear or its own weight.
snaggiest
English
Adjective
(head)
(snaggy)
snaggy
English
Adjective
(er)
Covered in snags, or similar sharp projections.