Deported from USA because I was denied an asylum. Now, after 5 years, planning to study in UK. I'm tempted to not to mention all this asylum process in my UK visa application since I spent all these 5 years back in my home country without trying to get back to US. Please advise if it is possible to not to mention deportation from US in my UK application.
It is of course possible for you to withhold this information. However, you should assume that the UK immigration people know about your deportation since the US and the UK share data extensively. If you fail to declare it on any application to the UK they will see it as an attempt at deception and you will attract a ten year ban.
Your deportation makes any visa application more complex. If you intend to apply to the UK you should find a good lawyer who specialises in UK immigration and take their advice.