From what I’ve read on this site and elsewhere, the root “man” was originally sex-neutral; the sex-specific terms were “wifman” (which later became “woman”) and either “werman” or “wepman”. The male-specific prefix has long been lost in this context, but does it survive anywhere else? I.e., what would a modern reconstruction of the word “werman” or “wepman” look like?
The Old English word wer survived into Middle English as "were" in both the senses of "male human" and "husband". Wer(e) is ultimately cognate not only with similar words in other Germanic languages but also with Latin "vir". The word wapman similarly survived into Middle English, meaning a male human being. Old English wǽpnman was from wǽpn meaning "weapon", but according to the OED, it was used here not in the sense of "weapon" but in the sense of "penis".
FumbleFingers rightly mentions werewolf, which is thought to derive from wer, and since at least the 19th century writers have occasionally coined words such as wer-bear and werecalf, though it's not clear that they have had the word wer or any knowledge of etymology in mind when doing so. The OED (in an entry not fully updated since 1926) casts doubt on the etymology:
The first element has usually been identified with Old English wer man were n.1, but the form were- in place of wer- (compare however were- and wergild wergild n.), and the variants in war-, var-, makes this somewhat doubtful.
However, more recent etymologies from Oxford University Press sound a less sceptical note: ODO (echoing the Concise Oxford Dictionary of English Etymology) says "the first element has usually been identified with Old English wer ‘man’". Other dictionaries such as AHD and Collins accept the "wer" etymology - as does M-W, adding in a note that "while some doubts about the word’s etymology still remain", "wer" is the most likely origin.
The word wergild or wergeld also survives. According to the OED, it means:
In ancient Teutonic and Old English law, the price set upon a man according to his rank, paid by way of compensation or fine in cases of homicide and certain other crimes to free the offender from further obligation or punishment.
Here's a citation from 1902:
F. Seebohm Tribal Custom in Anglo-Saxon Law i. 1 The Anglo-Saxon wergelds were stated, with perhaps one exception, in silver scillings.
Between the 17th and 19th centuries, there are also examples of were or wer being used as an abbreviated name for wergeld:
E. W. Robertson Hist. Ess. 236 (note) In later days it was a principle of Land-right that no free~man should be amerced ‘above his wer’.