Adjectives

(s)earlier, earliest(comparative and superlative of `early') more early than; most early“a fashion popular in earlier times”, “his earlier work reflects the influence of his teacher”, “Verdi's earliest and most raucous opera”

Adverbs

(r)earlier, beforeearlier in time; previously“I had known her before”, “as I said before”, “he called me the day before but your call had come even earlier”, “her parents had died four years earlier”, “I mentioned that problem earlier”
(r)sooner, earliercomparatives of `soon' or `early'“Come a little sooner, if you can”, “came earlier than I expected”
(r)in the first place, earlier, in the beginning, to begin with, originallybefore now“why didn't you tell me in the first place?”