FPKM/TPM are way of normalising the read counts. Link below explaining these: http://www.rna-seqblog.com/rpkm-fpkm-and-tpm-clearly-explained/

Now coming to other part, high FPKM/TPM values means high expression of a gene. But again this is relative to phenotype of interest and samples. If you have tumor and normal samples, an average FPKM higher value in tumors for certain genes means higher in tumors compared to normal would imply highly expressed genes in tumor.