From Wiktionary, the free dictionary
ضَحِكْتُمْ • (ḍaḥiktum) (form I) /dˤa.ħik.tum/
- second-person masculine plural past active of ضَحِكَ (ḍaḥika)
ضحكتم (form II)
- ضَحَّكْتُمْ (ḍaḥḥaktum) /dˤaħ.ħak.tum/: second-person masculine plural past active of ضَحَّكَ (ḍaḥḥaka)
- ضُحِّكْتُمْ (ḍuḥḥiktum) /dˤuħ.ħik.tum/: second-person masculine plural past passive of ضَحَّكَ (ḍaḥḥaka)