Synonyms for Besides:

adj.

accompanying (adjective)
auxiliary, ornamental, secondary, attached, extra, additional, Adorning, in addition to, along with, adjoining, supplemental, companion, affixed.
additional (adjective)
more.

adv.

all (adverb)
in any case.
also (adverb)
in addition, not to mention, too, furthermore, moreover, additionally, Including, together with, as well as, also, And, likewise, further.

adv

additionally (adverb)
further, moreover.
along (adverb)
as well, in addition to.
also (adverb)
conjointly, along with, in addition, further, Including, And, too, also, moreover, to boot, as well as, additionally, likewise, over and above, not to mention, in conjunction with, furthermore, together with.

conj.

however (conjunction)
still.

n.

secondly, into the bargain, on the side, more than, on top of that, in excess of, exclusive of, exceeding, apart from, plus, supplementary to, supplementary, other than, not counting, in other respects, together with something, to boot, in conjunction with, with the exception of, and all, over and above, else, beyond, aside from, added to, in distinction to, conjointly. as, Because, inasmuch as, Since, explain, precisely, nay, look at. besides (noun)
as well, too, also, in any case, likewise.

prep.

in addition to (preposition)
supplementary.

Other synonyms:

supplementary, secondly, aside from, Because. nay. as, Since, plus. explain, precisely. look at. in addition
item.
yet
still.

Usage examples for besides

  1. Besides he's a man who is fond of his wife and child. – The Hampstead Mystery by John R. Watson
  2. He won't mind, and besides he won't see it. – The Sherrods by George Barr McCutcheon
  3. Besides even if we could, I don't think I'd go. – Ronicky Doone by Max Brand