Astra Giurgiu On 6 November 2014, De Amorim scored his first goal in
UEFA Europa League, netting in the 81st minute for a 1–1 home draw against
Celtic Glasgow.
FCSB On 13 August 2016, FCSB announced the signing of Amorim for an undisclosed fee, with the player agreeing to a five-year deal with a €10 million buyout clause.
Loan to Xanthi On 21 January 2019,
Xanthi officially announced the signing of William on a one-and-a-half-year loan. On 29 September 2019, he scored in a 3–1 home win against
Volos. On 5 December 2019, William scored in a 3–0 home win against
Apollon Larissa for the second leg of the
Greek Cup round of 32, which helped his team secure a place in round of 16. ==Personal life==