infinito, endless, infinite.
inflamación, f., inflammation.
inflamatorio, inflammatory.
inflexible, relentless.
informalidad, f., indiscretion, neglect of conventionalities.
informarse (de), to make inquiries (about), investigate.
infranqueable, insurmountable.
infructuoso, fruitless, unsuccessful.
infundir, to pour, infuse, inspire (with); arouse.
ingeniero, engineer.