There are 14 13-letter words that start with 'cla'.
| cladistically | clairaudience |
| clairvoyances | clairvoyantly |
| clamorousness | clandestinely |
| clandestinity | clapperclawed |
| clarification | clarinettists |
| classlessness | claudications |
| claustrophobe | clavichordist |
Note: These 14 13-letter words that start with 'cla' are found from the USA & Canada version of the tournament Scrabble word list.
Also see words start with clas, clam, clan, clar, clad, clav, clay, clai, clau, clap, claw, clac, clat, claq, clab, clag, claf, clax.
4-letter words start with 'cla' (7)