Like a nerd; having the traits of a nerd.(adjective)
Wiktionary.org : Text is available under the Creative Commons Attribution-ShareAlike License
Use "nerdish" in a sentence
"He has the ability to play almost anything and I tthink he has a kind of nerdish good looks to boot."
"Actually, I wish I'd have followed through on my early nerdish instincts in 1987, rather than way belatedly in the oughts."
"It was a far cry from the geeky glasses and garish ties he sported during his early Blair years when he was dubbed "Brains" after the nerdish Thunderbirds puppet."