Meaning of the Sanskrit Word: tapasvinam

  tapasvinām—persons undergoing severe penances    SB-4.21.31, Madhya 24.217
  tapasvinam—undergoing great austerities and penances    SB 6.7.25
  tapasvinām—suffering material pangs    SB 4.22.15

Can't find any compound Sanskrit words containing tapasvinam.