Okay then, let's try some syntactic category tests…
Verb:
can be preceded by modal verbs, e.g. "he can practise ground", "I must practise ground"; NO.
form can change to indicate temporal contrasts, e.g. "practised ground"; NO.
can combine with a noun phrase (NP), e.g. "they practise ground NP[midgets]"; NO.
can be substituted by or be linked to the verb proform "do", e.g. "you practise ground, do you?", "BMMF practise ground and so does otherjames"; NO.
Noun:
can be preceded by a determiner, e.g. "the practice ground", "a practice ground"; YES.
can be preceded by adjectives, e.g. "the barren practice ground", "the new practice ground"; YES.
can combine with a verb phrase (VP) to make a complete sentence, e.g. "the practice ground VP[opens]", "practice grounds VP[give people somewhere to practise]"; YES.
can be pluralised, e.g. "practice grounds"; YES.
can be substituted by a pronoun (like 'it'), e.g. "it's a great facility"; YES.
can be an appropriate answer to a 'what' question, e.g. "what's that place you go to improve your skills?"; YES.
I could go on, seeing as you're universally challenged.
So tempted to merge this post with https://www.lfgss.com/thread9072.html