This is the 6588th most frequent Polish word.
deklaracja
"Declaration" - a formal or explicit statement or announcement.
Here, 'deklaracja' refers to an official document affirming one's intent to participate.
Podpisałem deklarację uczestnictwa w projekcie.
I signed the declaration of participation in the project.
In this sentence, 'deklaracja' signifies a verbal or written expression of intention to help.
Jego deklaracja pomocy była bardzo mile widziana.
His declaration of assistance was greatly appreciated.
This usage denotes a specific document used for reporting goods when traveling across borders.