Shankaracharya - A monk of the ashrams established by Sri Adi Shankarcharya. Example: Chandrasekharendra Saraswati.
Maharishi - A great sage. Example: Maharishi Vyasa, whose greatness requires no description either.
Paramhansa - A God-realized Supreme Saint. He has transcended the Three Gunas. Example: Sri Ramakrishna Paramhansa.
Paramguru - The Guru of Gurus. Example: Adi Shankaracharya is the Param Guru for all the shankaracharyas.
Rishi - A great sage. Example: Agastya.
Sadhaka - A spiritual aspirant. Example: you and me.
Saint - A holy man. Example: So many saints are there.
Satguru - The God Himself come as a human, Ishvara in human form is Satguru. Example: Sri Krishna.
Swami - A monk of the order of Swami's established by Shankaracharya. (Although I believe other also uses it)
Godman - A God-realized saint, or an avatar, i.e. A man who is believed to be God Himself. (It is usually used as a negative term thus I have no examples).
[a]: Autobiography of a Yogi, Paramhansa Yogananda, Chapter 1, footnote 3.
[b]: Satguru is God manifested in man, according to 'Rebirth is Optional' by Om Khera.