Bridge bidding - how do I decide whether or not to bid 1NT with weakness in a particular suit?
Your partner's response(s) ought to give you a good idea of whether a no trumps contract is the correct one to pursue, or if you might be better off looking elsewhere.

Perhaps your partner will bid Stayman over your NT bid.  If you find a satisfactory fit in hearts or spades, then the question of whether you have a shortage somewhere else becomes irrelevant (in fact, it turns into a bonus).

Otherwise, your partner may well - indeed, is statistically quite likely to - try to bid the suit that you are weak in.  If he does, then this reinforces your initial assumption that a no trumps contract may be a good place to be.

If your partner avoids the suit you are weak in - especially if he avoids it twice, then perhaps NT is not such a good idea.  However, if this is the case then he has almost certainly bid in a suit that you hold 4 cards in, by now.  If so, you have a pretty good option to shift to, outside of no trumps!