Memorization and repetition will indeed carve out the sharp memories of new vocabulary that are important for you to learn. However, it is not impossible you forget occasionally. On the other hand, you may need to check out the Trinity college Glasgow if you have to acquire the UK visa soon.
To get around this ‘senile’ moment, you can use the mnemonic method for a number of important words. Mnemonics can help to fit the words in your mind more effectively. Basically, mnemonics is a unique visual narrative depiction method that you can associate with words you want to remember. For example, you’re learning Spanish and it’s hard to remember the verb “caber” means “to load something (to fit)”. You can make up a visual narrative in your brain a big bear (bear) squeezed in the cab window (cab) that darted in the streets.
Or, “sausage” in German which means “wiener”. You can imagine someone who is on the championship podium after winning the sausage eating contest.
This association (caber -> cab, bear -> loading a flower in a taxi) will make it easier for you. Perhaps it will first sound troublesome, but train this association several times and you will be able to realize how silly and memorable the visualization can be very effective. So long over time, you no longer need to use this method to remember foreign vocabulary.