| immensely |
| immortal(adjective, constant, abundant, unrestrained, infinite) |
| immutable(adjective, lasting, permanent, everlasting, unending) |
| imperishable(adjective, continuous, vast, lasting, permanent) |
| in perpetuity(expression, adverb, continuously, forever, perpetually) |
| incomprehensible |
| indefinite(adjective, endless, lasting, permanent, unlimited) |
| indeterminate(adjective, constant, abundant, unrestrained, immense) |
| infinitely |
| innumerable |
| lasting(adjective, continuous, vast, permanent, everlasting) |
| late(adjective, slow, boring, tedious, rambling) |
| lingering(adjective, slow, boring, tedious, late) |
| long-drawn-out(adjective, slow, boring, tedious, late) |
| long-winded(adjective, slow, boring, tedious, late) |
| measureless(adjective, constant, absolute, abundant, endless) |
| monotonous(adjective, constant, abundant, unrestrained, infinite) |
| multitudinous(adjective, constant, abundant, unrestrained, infinite) |
| never-ceasing(adjective, present, continuous, endless, everlasting) |
| neverending(adjective, adverb, present, vast, extending) |