Similar-sounding words in the dictionary:
3 letters:
cid, cyd, cyr, dim, gym, him, jim, kim, kym, lim, mim, rim, sam, sib, sic, sid, sig, sil, sin, sip, sis, sit, som, sum, syd, syn, tim, vim, yim, zim, sim, sym
5 letters:
sieve, simms, sims', singh, symms, timme
6 letters:
simmer, symmes