syn- /sin-/, sy- /si-/, syl- /sil-/, sym- /sim-/ or sys- /sis-/

Signifying together, with

• self-glorification
• self-glorious
• self-governing
• self-government
• self-gracious
• self-harm
• self-harming
• self-hate
• self-hatred
• selfheal
• self-healing
• selfheals
• self-help
• self-heterodyne
• selfhood
• selfhoods
• self-humiliation
• self-hypnosis
• self-hypnotism
• steeded
• steeding
• steeds
• steed up
• steedy
• steek