Ploidy refers the number of sets of chromosomes in a cell, e.g. haploid(n) & diploid(2n).
Euploidy refers to complete set(s) of chromosome, e.g. 23 or 46 or 69 chromosomes in human.
Aneuploidy is non-euploidy, i.e. one extra (Down’s syndrome) or one missing chromosome (Turner’s syndrome).Polyploidy is the state of having multiple sets of chromosomes (i.e. tetraploid, hexaploid); there are two types:-

Allopolyploidy/alloploidy is the doubling of chromosome sets in a hybrid species.

Autopolyploidy is the doubling of chromosome sets within the same species.