diligent
energetic
active
ardent
assiduous
constant
continuing
determined
dogged
dynamic
enduring
enthusiastic
faithful
fervent
hard
hardworking
immutable
inalterable
indefatigable
indomitable
industrious
inexhaustible
insistent
invincible
laborious
lasting
lively
loyal
never idle
never-tiring
obstinate
patient
patient as Job
permanent
perseverant
persevering
persistent
persisting
pertinacious
plodding
plugging
preoccupied
rapt
relentless
resolute
sagging
sedulous
single-minded
sleepless
slogging
remorseless
ruthless
steadfast
steady
strenuous
unceasing
unswerving
untiring
vigorous