This is the 4391st most frequent Russian word.
ведущим
"Leading" or "host."
Here, 'ведущим' implies taking charge or being the leader in a situation.
Быть ведущим в споре нелегко.
To be leading in a dispute is not easy.
In this sentence, 'ведущим' refers to the role of a host or presenter in a program.
Я смотрел программу, где он был ведущим.
I watched a program where he was the host.
'ведущим' here describes something that is leading or prominent in its field.