Nowadays have a long time for proverbs (6)
I believe the answer is:
adages
'for proverbs' is the definition.
('adage' can be a synonym of 'proverb')
'nowadays have a long time' is the wordplay.
'nowadays' becomes 'AD' (AD, Anno Domini, as opposed to BC, Before Christ).
'have' says to put letters next to each other.
'a long time' becomes 'ages' (ages can mean a very long time).
'ad'+'ages'='ADAGES'
(Other definitions for adages that I've seen before include "'Proverbs, true sayings (6)'" , "Proverbs, wise sayings" , "'Proverbs, saws (6)'" , "Old sayings, proverbs" , "Much-used wise sayings" .)