Could somebody tell me please that what is the word that you use for a person who lost most of his hair?(he is not bald yet)
That person is said to be balding or going bald.
They are balding. Here is the link to balding in Cambridge Dictionaries online.
Balding, as the others say.
Yet there is the subtle shading of 'receding' ie, the hair is disappearing from the front, but there's some still at the back.
Which would lead to variations on how people try to hide that fact...
Comb-over - taking long hair from one side & combing it over the 'shiny bits', which nearly works unless it's windy [Google 'Bobby Charlton']
Known, as I understand it, in Japanese as a 'bar-code', from the similarity to the identifying marks on the side of any grocery product you scan through a till in the supermarket.
The alternative 'cure' - whilst not really fixing it - is to shave it all off.... Known as a 'Jean-Luc Picard' or just 'Picard', after the Captain of the USS Enterprise, Star Trek, the next generation.