our elders had not filled our heads with unnecesserary advic

well-meant adj.出自善意的
如:I offered her well - meant advice.我对她好意相劝.
而分开写则不是形容词,well meant 当作一个固定短语,作状语,意为:"本意良好的,出于好心的".
well meant or otherwise 出于善意或者其他原因.
句意:我们的长辈们,出于善意或者其他原因,没有给我们灌输不必要的建议.