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ymddwyn

to behave

"ymddwyn" means "to behave" in Welsh. Full conjugation table with present, imperfect, preterite, future, conditional, and imperative tenses.

Present

Presennol

PersonForm
I (fi)ymddygaf
You sg. (ti)ymddygi
He/She (fe/hi)ymddwg
We (ni)ymddygwn
You pl. (chi)ymddygwch
They (nhw)ymddygant
Impersonalymddygir

Imperfect

Amherffaith

PersonForm
I (fi)ymddygwn
You sg. (ti)ymddygit
He/She (fe/hi)ymddygai
We (ni)ymddygem
You pl. (chi)ymddygech
They (nhw)ymddygent
Impersonalymddygid

Preterite

Gorffennol

PersonForm
I (fi)ymddygais
You sg. (ti)ymddygaist
He/She (fe/hi)hi
We (ni)ymddygasom
You pl. (chi)ymddygasoch
They (nhw)ymddygasant
Impersonalymddygwyd

Pluperfect

Gorberffaith

PersonForm
I (fi)ymddygaswn
You sg. (ti)ymddygasit
He/She (fe/hi)ymddygasai
We (ni)ymddygasem
You pl. (chi)ymddygasech
They (nhw)ymddygasent
Impersonalymddygasid

Future

Dyfodol

PersonForm
I (fi)ymddyga i
You sg. (ti)ymddygi di
He/She (fe/hi)hi o
We (ni)ymddygwn ni
You pl. (chi)ymddygwch chi
They (nhw)ymddygan nhw

Conditional

Amodol

PersonForm
I (fi)ymddygwn
You sg. (ti)ymddygit
He/She (fe/hi)hi
We (ni)ymddygem
You pl. (chi)ymddygech
They (nhw)ymddygent
Impersonalymddygid

Imperative

Gorchmynnol

PersonForm
I (fi)-
You sg. (ti)ymddwg
He/She (fe/hi)ymddyged
We (ni)ymddygwn
You pl. (chi)ymddygwch
They (nhw)ymddygent
Impersonalymddyger

Example sentences

Pe bai bywoliaeth pobl yn cael ei beryglu mewn unrhyw ddiwydiant arall, ni fyddai'r Blaid Lafur yn ymddwyn fel hyn.

If livelihoods were jeopardised in any other industry, there's not a chance that the Labour Party would behave in this way.

C1

Mae hon yn ffordd ofnadwy i ni ymddwyn.

This is a dreadful way for us to carry on.

B1

Further reading

Welsh Verb Conjugation — All Tenses, Full Tables, Clear Patterns →The Welsh Verb Bod (To Be) — Every Form, Every Tense →Welsh Pronunciation — It's Actually Easier Than English →Best Apps to Learn Welsh (2026) →Browse all Welsh verb conjugations →

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Other Welsh verbs

euro

to gild

uno

to join

duo

to become black

mela

to gather nectar to make honey

dal

to catch

trio

to try

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