changeless
constant
hard-and-fast
invariant
strict
unvarying
abiding
accordant
alike
automatic
balanced
blah
broken-record
consistent
consonant
continuous
correspondent
drearisome
dreary
dry
dryasdust
dull
dusty
enduring
equable
equal
eternal
even
everlasting
fast
fixed
flat
harping
homogeneous
humdrum
immovable
immutable
inalterable
incommutable
inconvertible
indefeasible
inert
inflexible
insusceptible of change
intransmutable
irretrievable
irreversible
irrevocable
jog-trot
lasting
level
long-winded
constitutional
definite
habitual
indispensable
inevitable
infallible
outward
physiological
unalterable
unchanging
unfailing
variable