Repeatedly Old Bill’s covering up unacceptable things (6)
I believe the answer is:
taboos
'up unacceptable things' is the definition.
The answer and definition can be both human attributes as well as being plural nouns.
Maybe they are linked in a way I don't understand?
'repeatedly old bill's covering' is the wordplay.
'repeatedly' shows that letters should be duplicated.
'old' becomes 'o' (common abbreviation eg in OE for Old English).
'bill's' becomes 'tab's' (a tab is a bill at a bar).
'covering' is an insertion indicator.
'o' doubled is 'oo'.
'oo' placed into 'tabs' is 'TABOOS'.
Can you help me to learn more?
(Other definitions for taboos that I've seen before include "Prohibitions on things not to be done" , "They're forbidden by religion or social custom" , "restrictions" , "No-nos" , "Superstitious bans or prohibitions" .)