Synonyms for Basically:

adv.

all (adverb)
fundamentally, essentially.
fundamentally (adverb)
in essence, essentially, radically, at heart, primarily.
originally (adverb)
radically.
severely (adverb)
grimly, dryly, curtly, exactingly, shortly, sternly, bluntly, icily, briskly, keenly, rigorously, oppressively, acutely, intensely, demandingly, correctly, Rawly, matter-of-factly, tartly, meticulously, harshly, severely, acerbically, intolerantly, Acrimoniously, bleakly, gruffly, ascetically, imperially, dourly, strictly, coolly, crisply, critically, Leanly, sharply, stringently, precisely, brusquely, cuttingly, sparely, abruptly, piquantly, frostily, caustically.
topically (adverb)
thematically, theoretically, conceptually, topically, axiomatically, hypothetically.

adv

at heart (adverb)
at bottom.
in reality (adverb)
at heart.
originally (adverb)
radically.
principally (adverb)
importantly.
severely (adverb)
fundamentally, dourly, brusquely, acerbically, harshly, icily, shortly, keenly, Acrimoniously, intolerantly, precisely, Rawly, strictly, correctly, caustically, rigorously, crisply, grimly, severely, critically, oppressively, sternly, intensely, matter-of-factly, curtly, dryly, demandingly, austerely, imperially, gruffly, cuttingly, starkly, acutely, piquantly, ascetically, briskly, Leanly, exactingly, sharply, frostily, bleakly, coolly, tartly, sparely, meticulously, bluntly, abruptly, stringently.
topically (adverb)
thematically, theoretically, conceptually, topically, axiomatically, hypothetically.

n.

at the end of the day, importantly, the fact (of the matter) is, first, not just any.... at bottom, at heart, surface. basically (noun)
essentially, au fond, fundamentally, in essence.
fundamentally (noun)
radically.

Other synonyms:

importantly. first. Other relevant words:
au fond, at heart, radically, at bottom, in essence.