A word, probabaly meaning loser, or someone soon to recieve a kicking. Unfortunately as no one of any remote intelligence has ever used the word in context, the speculation to it's meaning is still rife.
Generally heard from the mouths of Neds accosting some other neds or worse, some poor innocent normal youth who doesn't aim to be on a Daytime TV chat show by the time they're 25.
If a Ned refers to you as 'a pure wee bam' then run. The buckie's gonnie get ye
'He's a wee bam man.'
'Pure bunch of bams'