Shallower, shallowest. More shallow, most shallow. Both forms are acceptable, but the first (..er, ..est) is probably more commonly used.
shallower
The comparative form of in is inner.
The comparative form of solid is solider
comparative - merrier superlative - merriest
"Shine" is a verb and a noun and, as such, does not have a comparative form. The comparative form of the adjective shiny is shinier.
shallower
Comparative: Shallower Superlative: Shallowest
Comparative: shallower Superlative: shallowest
shallower, shallowest
The comparative form of busy is busier.
The comparative form of dreamy is dreamier
The comparative form of friendly is friendlier.
comparative form is cleaner superlative form is cleanest
The comparative form of "central" is "more central."
The comparative form of many is more
The comparative form of "clean" is "cleaner."
The comparative form of friendly is friendlier.