White people put on a pound, you hear (7)
I believe the answer is:
albumen
'white' is the definition.
(thesaurus)
'people put on a pound you hear' is the wordplay.
'people' becomes 'men' (man is a kind of person).
'put on' means one lot of letters go next to another.
'pound' becomes 'lb' ('lb' can be a synonym of 'pound'**).
'hear' shows a homophone (sound like).
'you' is a homophone of 'u'.
'a'+'lb'+'u'='albu'
'men' put after 'albu' is 'ALBUMEN'.
(Other definitions for albumen that I've seen before include "Egg's white" , "Egg-white" , "White poacher" , "The white part of an egg" .)