inopportune moment (noun) off-year: unsuitable timing
Sinonime: dogged, impassable, impregnable, insuperable, insurmountable,
invincible, invulnerable,
obstinate,
pertinacious,
resolute,
ruthless,
staunch,
stubborn, unassailable,
unbeatable, unconquerable, undefeatable, unflinching, willful
Antonime: beatable, conquerable,
unstable,
weak,
yielding