I am in my final year and doing a game in Unity. The professor has clearly stated that the idea needs to be novel and not some clone or usual ideas.

I don't quite get it. So does that mean I have to forgo all the common RTS, FPS, RPG, puzzles and so on type of game ideas and come up with a completely new one? Counter strike was one of the previous FPS games that I can think of and now we have Battlefield 4 and so on. So does that make Battlefield 4 no longer novel or it is novel in its own way?

Wanted to make an FPS game but honestly having a major creative mental block to find something novel about it. Can I get some ideas.

I don't think your professor expects you to invent a new game genre, but I think he's best suited to answer that question than anyone here. If you have doubts about your task, you should ask him.

On the other hand, if you need an original idea for a game, this generator sometimes provides interesting ideas.

So does that make Battlefield 4 no longer novel

Actually this is probably a bad example because there is nothing Novel about Battlefield 4.

Maybe your proffessor means something like a FPS with No guns or an RTS where instead of telling units what to do, you are an actual unit and the computer tells you what to do.

I think he just means don't make a clone, When I was in school the students would just make clones of whatever game was popular at the time.

By "Novel" I think he just means an original concept inside one of the genres. I'm sure he's just tired of seeing super mario and counter strike clones.

Needed to fix this I somehow didn't read your last line, If you want to make an fps you have a few options. Try coming up with a new multiplayer game type,

or add a fresh feature to make a single player game "pop".

Off the top of my head-

Add some RPG elements into your FPS, the more your character performs repetitive actions he becomes more proficient.

Running 8km increase your speed by 1%

Firing 500 bullets from a sidearm gives you an extra clip or max clip size increase by 2

Taking 5k damage you increase damage resistance by 2%

ETC.

Just make sure you highlight these features with a screen pop up that congratulates the player or a skill tree.

Take a new spin on inventory management.

You can only carry 2 weapons at once but you can teleport in extra munitions or new weapons once you unlock them.

Add different ammo types to make certain weapons more effective against differing enemies.

Add overheating and degradation into your weapons giving the player a sense of fear.

ETC.

Add a interactive world mechanic.

As you progress you can interact with world objects to give you an upper hand, more than just explosive barrels. Like you can make ladders or boxes to reach new areas of the level.

Lockable/blockable doors and hallways to give strategic options.

Movable items to create a semi-puzzle environment.

I could keep going, FPS isn't really my strong point and I'm sure you could name games with these mechanics but it's just to help your creative fluids get moving.

As others have said, ask your professor. But in general I don't think anyone would require 100% novelty. I would say that Portal, Revolver, Left 4 Dead, Splatoon or Antichamber for example show some novelty. The main gameplay loop is significantly different than many FPS games. Portal and Antichamber aren't even really shooters. Whereas most of the currently popular FPS games are merely improving or polishing an existing formula.

If you go outside the FPS genre there seems to be much more room for experimentation. For example, World of Goo, Braid, fl0w.

Some years back I ran a group called Game Idea a Day on the Great Games Experiment site (sadly defunct now). It's easier than you think, you just need to get your mind out of the channels carved by what's popular right now. Look at old games, weird games, board games, card games, theatre, etc.