IPA: //rɪˈplɛnɪʃ//
KK: /plɛnɪʃ/
To fill something up again or to restore it to a full state.
After the storm, we need to replenish the supplies in the emergency kit.
Past: replenished
Past Participle: replenished
Plenish is derived from the root "plenus" (meaning full) in Latin, combined with the suffix "-ish" (meaning to make or to cause to be). The word "plenish" means to make full or to fill up.
Think of 'full' ('plenus') and remember that 'plenish' means to make something full.